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2020

What I learned in 2020.

2020-12-17

Nginx - brotli behavior

gzip_vary on; will affect brotli_static. brotli_static will look this config.

2020-12-04

GCP - Internal Load Balancer Behavior

Internal Load Balancer 192.168.0.101 have a Instance Group contains

  • 192.168.0.3
  • 192.168.0.4

in 192.168.0.3 curl 192.168.0.101, will always request to 192.168.0.3

in 192.168.0.4 curl 192.168.0.101, will always request to 192.168.0.4

2020-12-03

CN2 network - go out from China

  • 59.43.. is CN2 GIA better
  • 202.97.. is CN2 GT

Traceroute from China: https://tools.ipip.net/traceroute.php

curl - get current ip and geo location in China

curl https://myip.ipip.net\?json
当前 IP:183.240.8.10  来自于:中国 广东 广州  移动

Kubernetes - resource.memory Mi vs M

Mi = 1024*1024 = 1048576

M = 1000*1000 = 1000000

2020-11-20

k9s - Install k9s on Ubuntu Linux

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
# brew install derailed/k9s/k9s
brew install k9s

ref:

k3sup

https://github.com/alexellis/k3sup

curl -sLS https://get.k3sup.dev | sh
sudo install k3sup /usr/local/bin/

k3sup --help

ssh-keygen -f ~/.ssh/k3s -N ""

Add ssh-rsa.pub https://cloud.google.com/compute/docs/instances/adding-removing-ssh-keys#block-project-keys https://console.cloud.google.com/compute/metadata/sshKeys

export SSH_USER=rammus
export MASTER_IP=10.0.0.2
k3sup install --ip $MASTER_IP --user $SSH_USER --ssh-key ~/.ssh/k3s

export KUBECONFIG=/home/rammus_xu/kubeconfig
kubectl get node -o wide

export AGENT_IP=10.0.0.3
k3sup join --ip $AGENT_IP --server-ip $MASTER_IP --user $SSH_USER --ssh-key ~/.ssh/k3s

2020-11-12

Kuberntes - Pod inject/hijack/debug

        command: ["/bin/sh", "-c"]
        args:
        - |
          tail -f /dev/null

2020-11-10

MongoDB - not master and slaveOk=false

rs0:SECONDARY> show dbs
...
    "errmsg" : "not master and slaveOk=false",
    "code" : 13435,
    "codeName" : "NotMasterNoSlaveOk",
...
rs0:SECONDARY> rs.slaveOk()
rs0:SECONDARY> show dbs
admin   0.000GB
config  0.000GB
demo    0.000GB
local   0.000GB

MongoDB - Could not find host matching read preference { mode: \"primary\" } for set rs0

mongos> sh.addShard( "rs0/mongo-rs0-0.mongo-rs0.testing-mongo.svc.cluster.local:27017,mongo-rs0-1.mongo-rs0.testing-mongo.svc.cluster.local:27017,mongo-rs0-2.mongo-rs0.testing-mongo.svc.cluster.local:27017")
{
    "ok" : 0,
    "errmsg" : "Could not find host matching read preference { mode: \"primary\" } for set rs0",
    "code" : 133,
    "codeName" : "FailedToSatisfyReadPreference",
    "operationTime" : Timestamp(1604989375, 2),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1604989377, 1),
        "signature" : {
            "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
            "keyId" : NumberLong(0)
        }
    }
}

Debug:

  • config rs seems ok. not error log on mongos
  • mongo mongo-rs0-0.mongo-rs0.testing-mongo.svc.cluster.local:27017 rs0-0, rs0-1 rs0-2 are ok
  • rs0-0 is primary, read/write ok

Solution

mongos version and replica set version should be same.

This error occurs when:

  • shardsvr 4.0.20 + mongos 4.0.20 + configsvr 4.0.20 ✅
  • shardsvr 4.0.20 + mongos 4.0.20 + configsvr 4.4 ❌
  • shardsvr 4.0.20 + mongos 4.4 + configsvr 4.4 ❌
  • shardsvr 4.0.20, 3.6.6 mixed + mongos 4.0.20 + configsvr 4.0.20 ❌

2020-11-08

GKE - Node auto repair

https://cloud.google.com/kubernetes-engine/docs/how-to/node-auto-repair

GKE 會定期檢查 nodes,如果發生持續性的不健康, GKE 將會開始進行修復的程序。

以 Status:Ready 當作基準,以下情況會視為不健康: - 連續 10 分鐘 Status:NotReady - 連續 10 分鐘沒有任何狀態 - boot disk 用完硬碟空間,超過 30 分鐘

檢查最近的 operations,可以看到有沒有 auto repair

gcloud container operations list

2020-11-06

Kubernetes - Cusotmize a hostname

apiVersion: v1
kind: Pod
metadata:
  namespace: testing-mongo
  name: rammus-cf
  labels:
    name: rammus-cf
spec:
  hostname: rammus
  subdomain: cf
  containers:
  - name: nginx
    image: nginx
---
apiVersion: v1
kind: Service
metadata:
  name: cf
spec:
  selector:
    name: rammus-cf
  clusterIP: None

在 cluster 裡面可以用

curl rammus.cf

2020-11-03

GKE node auto repair notes

https://cloud.google.com/kubernetes-engine/docs/how-to/node-auto-repair

GKE 會定期檢查 nodes,如果發生持續性的不健康, GKE 將會開始進行修復的程序。

以 Status:Ready 當作基準,以下情況會視為不健康: - 連續 10 分鐘 Status:NotReady - 連續 10 分鐘沒有任何狀態 - boot disk 用完硬碟空間,超過 30 分鐘

Checking command:

gcloud container operations list

2020-10-30

Sign a GCS object

This will use gcs-service.json to generate a URL with expired time -d 1m. You can give someone the URL to access gs://rammus.cf/a-file.txt.

gsutil signurl -d 1m gcs-service.json gs://rammus.cf/a-file.txt

2020-10-22

Kubernetes - Install godaddy ssl certificate into secrets kubernetes.io/tls

cat 9faxxxxxxxxxxxxx.crt gd_bundle-g2-g1.crt > chain.crt
kubectl create secret tls --cert chain.crt --key generated-private-key.txt rammusxu.tw-tls

Test it on local:

  1. Add domain in /etc/hosts.
  2. Test it with CLI.
    ❌ curl -kv https://localhost/ -H 'Host: rammusxu.tw'
    👍 curl -kv https://rammusxu.tw
    
    ❌ openssl s_client -showcerts -connect rammusxu.tw:443
    👍 openssl s_client -showcerts -connect rammusxu.tw:443 -servername rammusxu.tw
    

2020-10-19

Nginx - Cache static with Cache-Control

        expires max;
        add_header                      Cache-Control "public";

Nginx - React app serve SPA htmls

ref: https://stackoverflow.com/questions/51367160/nginx-tries-to-find-index-html-in-a-directory-according-to-the-uri

        root /app;
        index index.html;
        location / {
            try_files $uri $uri/ /index.html;
        }

2020-10-16

Nginx - automatical content type

    include    mime.types;

path: - /usr/local/openresty/nginx/conf/mime.types; - conf/mime.types;

2020-10-07

MongoDB - Install mongo cli on Mac

ref: https://dba.stackexchange.com/questions/196330/is-it-possible-to-install-just-the-mongo-shell

brew tap mongodb/brew
brew install mongodb-community-shell

MongoDB - dump and restore

mongodump --gzip --db=test
# mongorestore <target> <folder>
mongorestore mongodb://localhost:27017 dump

2020-09-30

1 node(s) had volume node affinity conflict.

ref: https://cloud.google.com/kubernetes-engine/docs/concepts/persistent-volumes#pd-zones

Solution

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: slow
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-standard
  fstype: ext4
volumeBindingMode: WaitForFirstConsumer

2020-09-29

GKE don’t enable podpreset

no matches for kind "PodPreset" in version "settings.k8s.io/v1alpha1

kubectl apply -f podpreset.yaml
error: unable to recognize "podpreset.yaml": no matches for kind "PodPreset" in version "settings.k8s.io/v1alpha1"

no settings.k8s.io API

$ kubectl api-resources|grep settings.k8s.io
$ kubectl api-versions|grep settings.k8s.io

kubernetes - Taint and Tolerations

ref: https://godleon.github.io/blog/Kubernetes/k8s-Taints-and-Tolerations/

kubectl taint nodes gke-edge-tw-reserved-4c3f498d-068s preemptible=false:NoSchedule
kubectl taint nodes gke-edge-tw-reserved-4c3f498d-068s preemptible=false:NoExecute

preemptible=false:NoExecute will evicts all pod immediately

this means the pod can tolerate a taint node, so it can be deploy

  nodeSelector:
    cloud.google.com/gke-nodepool: reserved
  tolerations:
  - key: "preemptible"
    operator: "Equal"
    value: "false"

This can’t deploy

  nodeSelector:
    cloud.google.com/gke-nodepool: reserved
  tolerations:
  - key: "preemptible"
    operator: "Equal"
    value: "false"
    effect: "NoSchedule"

Error Message

  conditions:
  - lastProbeTime: null
    lastTransitionTime: "2020-09-29T07:37:03Z"
    message: '0/4 nodes are available: 1 node(s) had taint {preemptible: false}, that
      the pod didn''t tolerate, 3 node(s) didn''t match node selector.'
    reason: Unschedulable
    status: "False"
    type: PodScheduled

2020-09-17

Give a set of files a hash key

~ # md5sum a b
d41d8cd98f00b204e9800998ecf8427e  a
d41d8cd98f00b204e9800998ecf8427e  b
~ # md5sum a b | md5sum
fe84858e5913eaed7bf248d8b25a77d7  -
~ # md5sum a b | md5sum | cut -b-32
fe84858e5913eaed7bf248d8b25a77d7
~ # echo a > a
~ # md5sum a b | md5sum | cut -b-32
e849952f425275e21c0d5c46ba2549f5

2020-09-10

Kubernetes - VerticalPodAutoscaler

https://cloud.google.com/kubernetes-engine/docs/how-to/vertical-pod-autoscaling

  updatePolicy:
    updateMode: "Off"
$ kubectl get vpa my-vpa --output yaml
...
  recommendation:
    containerRecommendations:
    - containerName: my-container
      lowerBound:
        cpu: 536m
        memory: 262144k
      target:
        cpu: 587m
        memory: 262144k
      upperBound:
        cpu: 27854m
        memory: "545693548"

2020-09-09

Disable GKE release channel

ref: https://cloud.google.com/kubernetes-engine/docs/concepts/release-channels#updating_the_cluster_release_channel

It's not possible to exit RAPID channel for now.

$ gcloud container clusters update edge-tw --release-channel None --region asia-east1
ERROR: (gcloud.container.clusters.update) INVALID_ARGUMENT: Migrating off of releaseChannel RAPID is not supported.

fatal error: linux/version.h: No such file or directory

In file included from config.h:21,
                 from ae.c:45:
redis_config.h:38:10: fatal error: linux/version.h: No such file or directory
   38 | #include <linux/version.h>
      |          ^~~~~~~~~~~~~~~~~
compilation terminated.
make[1]: *** [Makefile:190: ae.o] Error 1
make[1]: Leaving directory '/redis-cluster-proxy/src'
make: *** [Makefile:4: all] Error 2

Solution

apk add linux-headers

2020-09-06

Upgrade buildx version on Mac

https://gist.github.com/RammusXu/8eb867e2a2dedd3c07149016829da5c3

docker buildx version

mkdir -p ~/.docker/cli-plugins
BUILDX_VERSION="v0.4.2"
wget https://github.com/docker/buildx/releases/download/${BUILDX_VERSION}/buildx-${BUILDX_VERSION}.darwin-amd64 -O ~/.docker/cli-plugins/docker-buildx
chmod a+x ~/.docker/cli-plugins/docker-buildx

docker buildx version

2020-09-03

Nginx - Change host not found response status and content

curl localhost:8001/host "host:backend"
location /host {
    resolver 127.0.0.11;
    proxy_pass              http://$http_host$uri;

    proxy_cache_key                 $http_host$uri;
    proxy_cache_valid               200 60s;

    proxy_intercept_errors          on;
    error_page 502 503 =404 /;
}

location @host_not_found {
    echo "not found";
}

Host not found

frontend_1  | 172.18.0.1 - - - MISS [03/Sep/2020:09:01:52 +0000] "GET /host HTTP/1.1" 404 20 "-" "HTTPie/1.0.2" "-"
frontend_1  | 2020/09/03 09:01:52 [error] 6#6: *12 backend2 could not be resolved (3: Host not found), client: 172.18.0.1, server: , request: "GET /host HTTP/1.1", host: "backend2"
frontend_1  | 2020/09/03 09:01:53 [error] 6#6: *13 backend2 could not be resolved (3: Host not found), client: 172.18.0.1, server: , request: "GET /host HTTP/1.1", host: "backend2"
frontend_1  | 172.18.0.1 - - - MISS [03/Sep/2020:09:01:53 +0000] "GET /host HTTP/1.1" 404 20 "-" "HTTPie/1.0.2" "-"

Host found

backend_1   | 172.18.0.3 - - [03/Sep/2020:09:02:30 +0000] "GET /host HTTP/1.0" 200 6 "-" "HTTPie/1.0.2" "-"
frontend_1  | 172.18.0.1 - - - MISS [03/Sep/2020:09:02:30 +0000] "GET /host HTTP/1.1" 200 16 "-" "HTTPie/1.0.2" "-"
frontend_1  | 172.18.0.1 - - - HIT [03/Sep/2020:09:02:38 +0000] "GET /host HTTP/1.1" 200 16 "-" "HTTPie/1.0.2" "-"

2020-08-27

2020 cert-manager request a certificate with ingress in place

ref: https://kosyfrances.github.io/ingress-gce-letsencrypt/

Environment

  • kuberentes: v1.17.9-gke
  • cert-manager: v0.15.0
apiVersion: cert-manager.io/v1alpha2
kind: ClusterIssuer
metadata:
  name: ci-http01
spec:
  acme:
    email: rammus.xu@gmail.com
    server: https://acme-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: issuer-account-key-rammus
    solvers:
      - http01:
          ingress:
            class: ingress-gce
---
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  namespace: web
  name: china-landing
  annotations:
    kubernetes.io/ingress.class: "gce"
    cert-manager.io/cluster-issuer: ci-http01
    acme.cert-manager.io/http01-edit-in-place: "true"
spec:
  tls:
    - hosts:
        - rammus.dev
      secretName: rammus-dev-tls
  rules:
    - host: rammus.dev
      http:
        paths:
          - backend:
              serviceName: http-service-np
              servicePort: http
---
apiVersion: v1
kind: Service
metadata:
  name: http-service-np
  namespace: web
spec:
  type: NodePort
  ports:
  - name: http
    port: 80
    targetPort: http
  selector:
    app: http-app

2020-08-21

Copy docker image to another registry

ref: https://cloud.google.com/artifact-registry/docs/docker/copy-from-gcr#copy-gcloud

gcloud container images add-tag GCR-IMAGE AR-IMAGE

Nginx - CORS with map example

ref:

Docker Registry - Gitlab Registry

docker pull registry.gitlab.com/rammus.xu/docker-alpine:3.12.0
docker login registry.gitlab.com -u rammus.xu -p
docker pull nginx:1.19.2-alpine
docker tag nginx:1.19.2-alpine registry.gitlab.com/rammus.xu/docker-alpine:nginx-1.19.2
docker push registry.gitlab.com/rammus.xu/docker-alpine:nginx-1.19.2

docker pull registry.gitlab.com/rammus.xu/docker-alpine:nginx-1.19.2

Docker Registry - Github Registry

  • Can't pull without docker credential
    • docker login https://docker.pkg.github.com -u rammusxu -p
docker login https://docker.pkg.github.com -u rammusxu -p
docker pull nginx:1.19.2-alpine
docker tag nginx:1.19.2-alpine docker.pkg.github.com/rammusxu/docker-alpine/nginx:1.19.2-alpine
docker push docker.pkg.github.com/rammusxu/docker-alpine/nginx:1.19.2-alpine

docker pull docker.pkg.github.com/rammusxu/docker-alpine/nginx:1.19.2-alpine
Error response from daemon: Get https://docker.pkg.github.com/v2/rammusxu/docker-alpine/nginx/manifests/1.19.2-alpine: no basic auth credentials

2020-08-19

Dockerhub is rate limiting download layers

Community - https://www.reddit.com/r/docker/comments/i93bui/docker_terms_of_service_change/ - https://www.reddit.com/r/docker/comments/i9lxq3/docker_reduces_image_retaining_to_6_months_for/

Where's disk storage location(path) of GKE emptyDir

# docker container inspect k8s_packager-public_stream-5ad4d9decc14623f43ed1325_default_247be3c5-227d-46cc-9f9c-7aad8cfaeb47_0 | grep Source
                "Source": "/var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47/volumes/kubernetes.io~empty-dir/dist",
                "Source": "/var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47/volume-subpaths/workdir/packager-public/1",
                "Source": "/var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47/volumes/kubernetes.io~secret/default-token-vvrzk",
                "Source": "/var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47/etc-hosts",
                "Source": "/var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47/containers/packager-public/0fa5ef38",

# df /var/lib/kubelet/pods/247be3c5-227d-46cc-9f9c-7aad8cfaeb47 -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       2.0T  173G  1.8T   9% /var/lib/kubelet

2020-08-12

markdown 文件製作

https://docsify.js.org/#/

2020-08-10

istio on k3d

curl -L https://istio.io/downloadIstio | sh -
cp istio-1.6.7/bin/istioctl $HOME/bin/

# ~/.zshrc
export PATH=$HOME/bin:/usr/local/bin:$PATH

~ istioctl version
no running Istio pods in "istio-system"
1.6.7
brew install k3d
k3d cluster create dc0 --k3s-server-arg --disable=traefik --publish 8080:80
k3d cluster create dc1 --port 8081:80 --no-lb --k3s-server-arg --disable=traefik
kubectl create namespace istio-system
kubectl create secret generic cacerts -n istio-system \
  --from-file=samples/certs/ca-cert.pem \
  --from-file=samples/certs/ca-key.pem \
  --from-file=samples/certs/root-cert.pem \
  --from-file=samples/certs/cert-chain.pem

# Install istio
istioctl install \
    -f manifests/examples/multicluster/values-istio-multicluster-gateways.yaml

# Update coreDNS
kubectl apply -f - <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           upstream
           fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
        reload
        loadbalance
    }
    global:53 {
        errors
        cache 30
        forward . $(kubectl get svc -n istio-system istiocoredns -o jsonpath={.spec.clusterIP}):53
    }
EOF

ref: https://dev.to/bufferings/tried-k8s-istio-in-my-local-machine-with-k3d-52gg

Configure k3d on Mac zsh

brew instsall k3d
mkdir -p ~/.oh-my-zsh/custom/plugins/k3d/_k3d
k3d completion zsh > ~/.oh-my-zsh/custom/plugins/k3d/_k3d

vi ~/.zshrc
plugins=(... k3d)

2020-08-07

Testing websocket

npm install -g wscat
docker run -it --rm  -p 10000:8080 jmalloc/echo-server
wscat -c ws://localhost:10000

2020-08-06

GCP Monitoring - Response Throughput is including CDN hit

  • Miss 0
  • Hit 21688/s

Nginx - add_header is not working on index.html

✅

      location / {
        add_header                      "Cache-Control" "public, max-age=600000";
        index index.html;
      }

❌

      location / {
        add_header                      "Cache-Control" "public, max-age=600000";
        index index.html;
      }

CC 4.0 著作權懶人包

ref: https://xie.infoq.cn/copyright

<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-nd/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License</a>.

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

基於 CC 4.0 協議進行如下類型授權:

  • CC BY(署名):只要在使用時署名,那麼使用者可以對本創作進行轉載、節選、混編、二次創作以及商業目的使用。
  • CC BY-NC(署名+ 非盈利):只要在使用、公開時進行署名,那麼使用者可以對本創作進行轉載、節選、混編、二次創作,但不得將本創作或由本創作衍生的創作運用於商業目的。
  • CC BY-ND(署名 + 禁止演繹):只要在使用、公開時進行署名,並且對創作不加任何改動,那麼使用者可以使用本創作,包括將其運用於商業目的。
  • CC BY-NC-ND(署名 + 非盈利 + 禁止演繹):使用者可以對本創作進行轉載,但不得對本創作進行修改,亦不得依據本創作進行再創作,不得將本創作運用於商業用途。
  • CC BY-SA(署名+ 繼承):使用者可以對本創作進行轉載、節選、混編、二次創作,可以將其運用於商業用途,唯須署名作者,並且採用本創作的內容必須同樣採用本協議進行授權。
  • CC BY-NC-SA(署名+ 非盈利+ 繼承):使用者可以對本創作進行轉載、節選、混編、二次創作,但不得運用於商業目的,且使用時須進行署名,採用本創作的內容必須同樣採用本協議進行授權。

2020-08-05

No more google - Google alternatives

https://nomoregoogle.com/

Privacy-friendly alternatives to Google that don't track you

2020-08-03

Service mesh

https://www.youtube.com/watch?v=-KWvlW9CSn8

  • Istio
  • Linkerd
  • Kuma
  • Mosn

2020-07-30

製作 grouped bar chart online

https://codepen.io/pen/?&editable=true=https%3A%2F%2Fwww.highcharts.com%2Fsamples%2Fhighcharts%2Fdemo%2Fcolumn-basic%3Fcodepen https://www.highcharts.com/demo

2020-07-24

AB load testing in Alpine Linux

apk add apache2-utils
ab -n1000 -c10 -k http://localhost/

To generate ECDSA P-256 certificate with step-cli

step-cli: https://smallstep.com/cli/

brew install step

ref: https://linkerd.io/2/tasks/generate-certificates/#trust-anchor-certificate

step certificate create identity.linkerd.cluster.local ca.crt ca.key \
--profile root-ca --no-password --insecure

Import ssl cert to kubernetes secret

cat 34_120_61_244.crt IntermediateCA.crt > ip.crt

kubectl create secret tls web-ip1 \
  --cert 34_120_61_244.crt \
  --key 34_120_61_244.key \
  -n web

update cert

kubectl create secret tls web-ip1 \
  --cert 34_120_61_244.crt \
  --key 34_120_61_244.key \
  -n web --dry-run -o yaml \
  | kubectl apply -f -

2020-07-22

Nginx - Access-Control-Allow-Origin: *

Good

        more_set_headers                "Access-Control-Allow-Origin: $http_origin";

Bad

        more_set_headers                "Access-Control-Allow-Origin: *";

2020-07-14

Is possible to use ip address in ManagedCertificate in GKE?

No.

Error

The ManagedCertificate "my-ip1" is invalid: spec.domains: Invalid value: "": spec.domains in body should match '^(([a-zA-Z0-9]+|[a-zA-Z0-9][-a-zA-Z0-9]*[a-zA-Z0-9])\.)+[a-zA-Z][-a-zA-Z0-9]*[a-zA-Z0-9]\.?$'
apiVersion: networking.gke.io/v1beta2
kind: ManagedCertificate
metadata:
  name: my-ip1
spec:
  domains:
    - "34.120.100.100"

2020-07-06

Nginx - as an forward proxy server

https://www.alibabacloud.com/blog/how-to-use-nginx-as-an-https-forward-proxy-server_595799

server {
     listen  443;

     # dns resolver used by forward proxying
     resolver  114.114.114.114;

     # forward proxy for CONNECT request
     proxy_connect;
     proxy_connect_allow            443;
     proxy_connect_connect_timeout  10s;
     proxy_connect_read_timeout     10s;
     proxy_connect_send_timeout     10s;

     # forward proxy for non-CONNECT request
     location / {
         proxy_pass http://$host;
         proxy_set_header Host $host;
     }
}

curl https://www.baidu.com -svo /dev/null -x 39.105.196.164:443

2020-06-30

Github API - Delete branch with Personal Access Token

export INPUT_AUTH_TOKEN=
export GITHUB_REPOSITORY=
export GITHUB_HEAD_REF=

http DELETE "https://api.github.com/repos/$GITHUB_REPOSITORY/git/refs/heads/$GITHUB_HEAD_REF" \
    "Authorization: token $INPUT_AUTH_TOKEN"

2020-06-24

Linux - Get Geo infomation in curl

curl https://ipinfo.io/
{
  "ip": "59.124.114.73",
  "hostname": "59-124-114-73.hinet-ip.hinet.net",
  "city": "Taipei",
  "region": "Taiwan",
  "country": "TW",
  "loc": "25.0478,121.5319",
  "org": "AS3462 Data Communication Business Group",
  "timezone": "Asia/Taipei",
  "readme": "https://ipinfo.io/missingauth"
}
curl ifconfig.co/json
{
    "asn": "AS3462",
    "asn_org": "Data Communication Business Group",
    "city": "Taipei",
    "country": "Taiwan",
    "country_eu": false,
    "country_iso": "TW",
    "hostname": "59-124-114-73.HINET-IP.hinet.net",
    "ip": "59.124.114.73",
    "ip_decimal": 998011465,
    "latitude": 25.0478,
    "longitude": 121.5318,
    "region_code": "TPE",
    "region_name": "Taipei City",
    "time_zone": "Asia/Taipei",
    "user_agent": {
        "product": "HTTPie",
        "raw_value": "HTTPie/1.0.2",
        "version": "1.0.2"
    }
}

curl -s https://ipvigilante.com/$(curl -s https://ipinfo.io/ip)
{"status":"success","data":{"ipv4":"59.124.114.73","continent_name":"Asia","country_name":"Taiwan","subdivision_1_name":null,"subdivision_2_name":null,"city_name":null,"latitude":"23.50000","longitude":"121.00000"}}

Nginx Ingress will use default fake certificate

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  namespace: staging
  name: demo
  annotations:
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/ssl-redirect: "false" # Default:true
spec:
  tls:
  - secretName: staging-tls
  rules:
  - http:
      paths:
      - backend:
          serviceName: demo-web
          servicePort: http
curl -kvL https://api.r-live.swaggg.dev

* Server certificate:
*  subject: O=Acme Co; CN=Kubernetes Ingress Controller Fake Certificate
*  start date: Jun 24 04:25:00 2020 GMT
*  expire date: Jun 24 04:25:00 2021 GMT
*  issuer: O=Acme Co; CN=Kubernetes Ingress Controller Fake Certificate
*  SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.

2020-06-23

Intall Google Cloud SDK in docker image

FROM docker:stable

RUN \
    apk add curl bash python git && \
    curl https://sdk.cloud.google.com | bash -s -- --disable-prompts

ENV PATH $PATH:/root/google-cloud-sdk/bin

Linux - Get external ip in curl cli

ref: https://www.tecmint.com/find-linux-server-public-ip-address/

$ curl ifconfig.co
$ curl ifconfig.me
$ curl icanhazip.com
$ curl https://ipinfo.io/ip

Kubernetes - GKE/GCP proxy to internal load balancer

Internal load balancer

apiVersion: v1
kind: Service
metadata:
  namespace: default
  name: ilb-api
  annotations:
    cloud.google.com/load-balancer-type: "Internal"

    # This is beta. So it needs to follow this: https://stackoverflow.com/a/59658742/3854890
    # gcloud beta compute forwarding-rules update xxxxx --region us-central1 --allow-global-access
    # networking.gke.io/internal-load-balancer-allow-global-access: "true" # This is for same VPC different region.
spec:
  externalTrafficPolicy: Local
  type: LoadBalancer
  selector:
    role: api
  ports:
  - port: 80
    targetPort: http
    protocol: TCP

Proxy service to internal load balancer

apiVersion: v1
kind: Service
metadata:
  namespace: web
  name: api-proxy
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

---
kind: Endpoints
apiVersion: v1
metadata:
  namespace: web
  name: api-proxy
subsets:
  - addresses:
      - ip: 10.100.0.100
    ports:
      - port: 80

GKE - Internal Load Balancer don't need extra firewalls

ref: https://cloud.google.com/kubernetes-engine/docs/how-to/internal-load-balancing#global_access

no need to add additional firewalls. Default can access same region+project Internal Load Balancer.

  • Without global access, traffic originating from clients in your VPC network must be in the same region as the load balancer.
  • Global access is enabled per-Service using the following annotation: networking.gke.io/internal-load-balancer-allow-global-access: "true".
  • Global access is available in Beta on GKE clusters 1.16 and up.

2020-06-18

Linux - adduser without prompts

adduser runner --disabled-password  --gecos ""

Linux - Add sudoer group to user

echo "runner ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers &&\
usermod -aG sudo runner

Github Action Runner - Fix gifsicle: Command failed

Solution

ref: https://github.com/imagemin/imagemin-gifsicle/issues/37#issuecomment-577889854

apt-get install -y --no-install-recommends autoconf automake libtool dh-autoreconf

error /home/runner/_work/runner-demo/node_modules/gifsicle: Command failed.
Exit code: 1
Command: node lib/install.js
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
Arguments:
Directory: /home/runner/_work/runner-demo/node_modules/gifsicle
Output:
⚠ Response code 404 (Not Found)
  ⚠ gifsicle pre-build test failed
  ℹ compiling from source
  ✖ Error: Command failed: /bin/sh -c ./configure --disable-gifview --disable-gifdiff --prefix="/home/runner/_work/runner-demo/node_modules/gifsicle/vendor" --bindir="/home/runner/_work/runner-demo/node_modules/gifsicle/vendor"
config.status: error: in `/tmp/ee647f58-0c5e-49d4-995d-bf84ec21ed4e':
config.status: error: Something went wrong bootstrapping makefile fragments

2020-06-11

Failed to determine a valid solver configuration for the set of domains on the Order: no configured challenge solvers can be used for this challenge

That's because Let's encrypt HTTP01 doesn't support wildcard(*) domains.

So, we can't use *.rammus.cf in

apiVersion: cert-manager.io/v1alpha2
kind: Issuer
metadata:
  namespace: web
  name: rammus
spec:
  acme:
    email: rammus@rammus.cf
    server: https://acme-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: rammus
    solvers:
    - http01:
       ingress:
         class: nginx
---
apiVersion: cert-manager.io/v1alpha2
kind: Certificate
metadata:
  namespace: web
  name: rammus
spec:
  secretName: rammus-tls
  issuerRef:
    # The issuer created previously
    kind: Issuer
    name: rammus
  dnsNames:
  - 'rammus.cf'
  - '*.rammus.cf'
  - 'api.rammus.cf'

2020-06-05

gsutil - Verify a google service account with docker and a environment variable

docker run -it --rm --entrypoint bash gcr.io/cloud-builders/gsutil
sa='{key.json,....}'
gcloud auth activate-service-account --key-file=<(echo $sa)
gsutil ls gs://rammus.dev

2020-06-02

Kubernetes - Get client ip from Google Network Load Balancer

https://kubernetes.io/docs/tutorials/services/source-ip/#source-ip-for-services-with-typeloadbalancer

spec:
  externalTrafficPolicy: Local
  type: LoadBalancer

kubernetes issue: https://github.com/kubernetes/kubernetes/issues/10921

Direct server return (DSR)

https://blog.envoyproxy.io/introduction-to-modern-network-load-balancing-and-proxying-a57f6ff80236

2020-05-26

Nginx - get request connection id

ref: - https://stackoverflow.com/questions/17748735/setting-a-trace-id-in-nginx-load-balancer - http://nginx.org/en/docs/http/ngx_http_upstream_module.html#keepalive

    server {
      listen                          80 default_server deferred;

        set  $trace_id  $connection-$connection_requests;

        location / {
            proxy_set_header          Host 'api.swag.live';
            proxy_pass                https://api$request_uri;
            proxy_cache_key           api$request_uri;
            proxy_set_header X-Request-Id $trace_id;
        }
    }

Nginx - proxy_set_header will diable persistent connection

proxy_set_header
      upstream swaglive {
        server                        swaglive.web;
        keepalive                     16;
        keepalive_requests            100000;
      }

      proxy_http_version              1.1;
      proxy_set_header                Connection "";

HTML - Expires and Cache-Control

Cache-Control > Expires

  • Expires: HTTP 1.0
  • Cache-Control: HTTP 1.1

ref: https://blog.techbridge.cc/2017/06/17/cache-introduction/

2020-05-22

Nginx - use http header as variable

$http_name
ex:
$http_referer
$http_user_agent
$http_x_forwarded_for

Nginx - SSL_do_handshake() failed (SSL: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number) while SSL handshaking to upstream

       proxy_ssl_session_reuse off;

Nginx - server listen 80 default deferred

server {
  listen 80 default deferred;
  ...
}

ref: https://stackoverflow.com/questions/8449058/what-does-the-deferred-option-mean-in-nginxs-listen-directive

TCP_DEFER_ACCEPT can help boost performance by reducing the amount of preliminary formalities that happen between the server and client.

"deferred" is Linux-only. For example on FreeBSD it won't work

Nginx - Print cache status log

    log_format  main  '$remote_addr - $remote_user - $upstream_cache_status [$time_local] "$request" '
                     '$status $body_bytes_sent "$http_referer" '
                     '"$http_user_agent" "$http_x_forwarded_for"';


    access_log  logs/access.log  main;

2020-05-20

Nginx - proxy_pass cache prority

  1. proxy_cache_path inactive=10m
  2. Cache-Control: s-maxage
  3. Cache-Control: max-age
  4. proxy_cache_valid 200 2s;

https://github.com/RammusXu/toolkit/tree/master/docker/two-layer-nginx

2020-05-13

Probot - update file and create pull request

https://github.com/octokit/rest.js/issues/845#issuecomment-386108187

2020-05-05

Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.40/containers/json: dial unix /var/run/docker.sock: connect: permission denied

Solution

sudo chmod 777 /var/run/docker.sock

Install docker on Debian Linux

apt-get install     apt-transport-https     ca-certificates     curl     gnupg-agent     software-properties-common
sudo apt-key fingerprint 0EBFCD88
sudo add-apt-repository    "deb [arch=amd64] https://download.docker.com/linux/debian \
  $(lsb_release -cs) \
  stable"
sudo apt-get update
sudo apt-get install docker-ce docker-ce-cli containerd.io
docker run hello-world

ab benchmark is using 1 core

docker run --rm russmckendrick/ab ab -k -n 20000 -c 2000 https://rammus.cf/

Better to use multi-thread benchmark tool

docker run --rm williamyeh/wrk -t10 -c500 -d30 --latency https://rammus.cf

apk add wrk
wrk -t10 -c500 -d30 --latency http://localhost:3000

Can monitor this behavior with:

docker stats

ab will never over 100%, also need to care about how much resource you give it to docker machine.

2020-05-04

Pemission denied when volumeMounts configmap as file

https://github.com/kubernetes/kubernetes/issues/71356

     subprocess.call(['./demo.sh'])
   File "/usr/local/lib/python3.8/subprocess.py", line 340, in call
     with Popen(*popenargs, **kwargs) as p:
   File "/usr/local/lib/python3.8/subprocess.py", line 854, in __init__
     self._execute_child(args, executable, preexec_fn, close_fds,
   File "/usr/local/lib/python3.8/subprocess.py", line 1702, in _execute_child
     raise child_exception_type(errno_num, err_msg, err_filename)
 PermissionError: [Errno 13] Permission denied: './demo.sh'
kind: ConfigMap
metadata:
  name: tls-watch-config
data:
  app.py: |
    import subprocess
        subprocess.call(['./update-cert.sh', filename, target_proxy])

  update-cert.sh: |
    echo 'update'
      volumes:
      - name: workspace
        configMap:
          name: tls-watcher-config
          defaultMode: 0555

      containers:
      - name: tls-watcher
        image: python:3.8-alpine3.11
        volumeMounts:
        - name: workspace
          mountPath: /workspace
        workingDir: /workspace
        command: ["sh", "-c"]
        args:
        - |
          python -u app.py

2020-04-30

Generate an unique sha from multiple file in Mac

shasum *.json| shasum | cut -d' ' -f1

2020-04-24

Nginx: could not find named location

2020/04/24 09:34:31 [error] 7#7: *58 could not find named location "@gcsfiles" while sending to client, client: 10.4.4.2, server:

location ~* '^/(js|img|locale)/' {
  proxy_pass                      http://backend/$uri;
  proxy_cache_key                 rammus.cf$uri;
  add_header                      "Cache-Control" "public, max-age=3600";
  add_header                      Strict-Transport-Security "max-age=86400; includeSubDomains" always;

  proxy_intercept_errors on;
  error_page                      404 = @gcsfiles;
}

location = @gcsfiles {
  proxy_pass                      http://gcs/rammus.cf$uri;
  proxy_cache_key                 $http_host$uri;

  # Enabled HSTS
  add_header                      Strict-Transport-Security "max-age=86400; includeSubDomains" always;
  add_header                      "Cache-Control" "public, max-age=2592300";
}

It should be

location = @gcsfiles {
location @gcsfiles {
without =

2020-04-17

GKE ingress with managed-certificates

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: web
  namespace: default
  annotations:
    # gcloud compute addresses create gclb-web --global
    # gcloud compute addresses list
    networking.gke.io/static-ip: 1.1.1.1

    # kubectl apply -f certificate.yaml
    # gcloud compute ssl-certificates list
    networking.gke.io/managed-certificates: rammus-cf

spec:
  rules:
  - host: rammus.cf
    http:
      paths:
      - backend:
          serviceName: my-svc
          servicePort: http
  - http:
      paths:
      - backend:
          serviceName: my-svc
          servicePort: http
apiVersion: networking.gke.io/v1beta1
kind: ManagedCertificate
metadata:
  name: rammus-cf
spec:
  domains:
    - "rammus.cf"

2020-04-07

Test a website speed

docker run --rm -v "$(pwd)":/sitespeed.io sitespeedio/sitespeed.io:12.3.1 https://app.swag.live

2020-03-14

Find other LAN user's IP

arp -a

2020-03-13

中國的測速網站 https://www.17ce.com/

可以測試 CDN 效果

  • benchmark
  • warm up

2020-03-12

dnsmasq: unsupported option (check that dnsmasq was compiled with DHCP/TFTP/DNSSEC/DBus support)

Solution

apk --no-cache add dnsmasq-dnssec

這個錯誤發生在:

  • 使用 alpine linux apk add dnsmasq
  • Enable dnssec
# /etc/dnsmasq.conf
dnssec
conf-file=/usr/share/dnsmasq/trust-anchors.conf
dnssec-check-unsigned

or

# /etc/dnsmasq.conf
dnssec
trust-anchor=.,19036,8,2,49AAC11D7B6F6446702E54A1607371607A1A41855200FD2CE1CDDE32F24E8FB5
trust-anchor=.,20326,8,2,E06D44B80B8F1D39A95C0B0D7C65D08458E880409BBC683457104237C7F8EC8D
dnssec-check-unsigned

Success

nsmasq_1  | dnsmasq: started, version 2.80 cachesize 150
dnsmasq_1  | dnsmasq: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset auth DNSSEC loop-detect inotify dumpfile
dnsmasq_1  | dnsmasq: DNSSEC validation enabled
dnsmasq_1  | dnsmasq: configured with trust anchor for <root> keytag 20326
dnsmasq_1  | dnsmasq: configured with trust anchor for <root> keytag 19036

Parsing dnssec anchors in shell script(bash)

ref:

  • https://stackoverflow.com/questions/19908777/curl-and-xmllint-pipe
  • https://data.iana.org/root-anchors/root-anchors.xml
    curl -s https://data.iana.org/root-anchors/root-anchors.xml | \
      xmllint --format --xpath 'concat("trust-anchor=.,", /TrustAnchor/KeyDigest[1]/KeyTag, ",", /TrustAnchor/KeyDigest[1]/Algorithm, ",",/TrustAnchor/KeyDigest[1]//DigestType, ",", /TrustAnchor/KeyDigest[1]/Digest)' -
    
    curl -s https://data.iana.org/root-anchors/root-anchors.xml | \
      xmllint --format --xpath 'concat("trust-anchor=.,", /TrustAnchor/KeyDigest[2]/KeyTag, ",", /TrustAnchor/KeyDigest[2]/Algorithm, ",",/TrustAnchor/KeyDigest[2]//DigestType, ",", /TrustAnchor/KeyDigest[2]/Digest)' -
    

Commands of testing domain

apk add bind-tools
nslookup swag.live localhost
nslookup swag.live 127.0.0.1
dig @localhost swag.live
dig @127.0.0.1 swag.live
dig @8.8.8.8 swag.live
dig +trace swag.live
dig +short swag.live ns
dig @dnsmasq +dnssec swag.live
dig @dnsmasq +dnssec google.com

2020-03-11

Check multiple variables are not None in Python

ref: https://stackoverflow.com/questions/42360956/what-is-the-most-pythonic-way-to-check-if-multiple-variables-are-not-none

params = os.getenv('PARAMS')
sid = os.getenv('SID')
skey = os.getenv('SKEY')
if None in (params, sid, skey):
    print("Must have SID, SKEY, PARAMS")
    exit(1)

2020-03-10

GCS roles

Storage Object Admin

resourcemanager.projects.get
resourcemanager.projects.list
storage.objects.create
storage.objects.delete
storage.objects.get
storage.objects.getIamPolicy
storage.objects.list
storage.objects.setIamPolicy
storage.objects.update

Storage Object Creator

resourcemanager.projects.get
resourcemanager.projects.list
storage.objects.create

Storage Object Viewer

resourcemanager.projects.get
resourcemanager.projects.list
storage.objects.get
storage.objects.list

2020-03-09

Get nth line of stdout on linux

ref: https://stackoverflow.com/questions/1429556/command-to-get-nth-line-of-stdout

ls -l | sed -n 2p
ls -l | head -2 | tail -1

Sort GCS (google cloud storage) objects by date

ref: https://stackoverflow.com/a/51709554/3854890

gsutil ls -l gs://[bucket-name]/ | sort -r -k 2
Example:
~ gsutil ls -l gs://rammus.cf/download | sort -r -k 2
  62786148  2020-03-06T05:52:53Z  gs://rammus.cf/download/3.0.2.8087.086886.apk
  62732280  2020-03-04T03:07:33Z  gs://rammus.cf/download/3.0.1-8070.apk
  62729059  2020-03-02T16:25:22Z  gs://rammus.cf/download/3_0_1_8ca354.apk
  11  2020-03-02T16:25:03Z  gs://rammus.cf/download/

Measuring kubernetes dns

bash-5.0# time (for i in {1..100}; do host -U echoserver.ops > /dev/null ; done)

real    0m1.150s
user    0m0.445s
sys 0m0.278s
bash-5.0# time (for i in {1..100}; do host -U echoserver.ops.svc.cluster.local > /dev/null ; done)

real    0m1.762s
user    0m0.463s
sys 0m0.362s
bash-5.0# host -v echoserver.ops
Trying "echoserver.ops.ops.svc.cluster.local"
Trying "echoserver.ops.svc.cluster.local"
bash-5.0# host -v echoserver.ops.svc.cluster.local
Trying "echoserver.ops.svc.cluster.local.ops.svc.cluster.local"
Trying "echoserver.ops.svc.cluster.local.svc.cluster.local"
Trying "echoserver.ops.svc.cluster.local.cluster.local"
Trying "echoserver.ops.svc.cluster.local.google.internal"
Trying "echoserver.ops.svc.cluster.local"

bash-5.0# cat /etc/resolv.conf
nameserver 10.24.0.10
search ops.svc.cluster.local svc.cluster.local cluster.local google.internal
options ndots:5

2020-03-06

How does UDP request receiving responses.

  • SOCK_STREAM: TCP
  • SOCK_DGRAM: UDP

https://stackoverflow.com/questions/1815030/receiving-a-response-through-udp

  1. Client emits UDP packet.
  2. Router passes UDP packet to the Internet.
  3. Router remembers that client sent a UDP packet to server, and establishes a mapping in its memory.
  4. Server sends a UDP packet, probably on the same port.
  5. Router receives packet, and checks mapping to find client talked to server recently.
  6. Router passes packet to client.

https://ns1.com/resources/dns-protocol

DNS communication occurs via two types of messages: queries and replies. Both DNS query format and reply format consist of the following sections:

  • The header section contains Identification; Flags; Number of questions; Number of answers; Number of authority resource records (RRs); and Number of additional resource records.
  • The flag field contains sections of one or four bits, indicating type of message, whether the name server is authoritative; whether the query is recursive or not, whether request was truncated, and status.
  • The question section contains the domain name and type of record (A, AAAA, MX, TXT, etc.) being resolved. Each label in the domain name is prefixed by its length.
  • The answer section has the resource records of the queried name.

http://www-inf.int-evry.fr/~hennequi/CoursDNS/NOTES-COURS_eng/msg.html

Weave Scope - 監控 kubernetes 的工具

ref: https://www.weave.works/docs/scope/latest/installing/#kubernetes

安裝 Weave Scope

kubectl apply -f "https://cloud.weave.works/k8s/scope.yaml?k8s-version=$(kubectl version | base64 | tr -d '\n')"
Expose 服務到 localhost
kubectl port-forward -n weave service/weave-scope-app 4040:80
open -a "Google Chrome" "http://localhost:4040"

2020-03-05

Try to resolve a domain in kubernetes

Default /etc/resolv.conf is like:

nameserver 10.24.0.10
search default.svc.cluster.local svc.cluster.local cluster.local google.internal
options ndots:5

少於 5 個 dot (.) 將會先搜尋 search default.svc.cluster.local svc.cluster.local cluster.local google.internal

> host -v a.a.a.www.google.com
Trying "a.a.a.www.google.com"

> host -v a.a.www.google.com
Trying "a.a.www.google.com.ops.svc.cluster.local"
Trying "a.a.www.google.com.svc.cluster.local"
Trying "a.a.www.google.com.cluster.local"
Trying "a.a.www.google.com.google.internal"
Trying "a.a.www.google.com"

> host -v www.google.com
Trying "www.google.com.ops.svc.cluster.local"
Trying "www.google.com.svc.cluster.local"
Trying "www.google.com.cluster.local"
Trying "www.google.com.google.internal"
Trying "www.google.com"

2020-03-04

how-to-perform-ddos-test-as-a-pentester

https://pentest.blog/how-to-perform-ddos-test-as-a-pentester/

Install netstress on kali linux

apt-get update
apt-get install netstress

Run kali linux on Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: kali
  labels:
    app: kali
spec:
  ## Select node pool in GKE
  # affinity:
  #   nodeAffinity:
  #     requiredDuringSchedulingIgnoredDuringExecution:
  #       nodeSelectorTerms:
  #       - matchExpressions:
  #         - key: cloud.google.com/gke-nodepool
  #           operator: In
  #           values:
  #           - "pool-1"
  containers:
  - image: kalilinux/kali
    command: ["/bin/sh","-c"]
    args:
    - |
      tail -f /dev/null
    imagePullPolicy: IfNotPresent
    name: kali
  restartPolicy: Never

GKE NodeLocal DNSCache

https://cloud.google.com/kubernetes-engine/docs/how-to/nodelocal-dns-cache

  • Base on CoreDNS

Install dnsperf on alpine

ref: - https://github.com/ssro/dnsperf/blob/master/Dockerfile - https://github.com/guessi/docker-dnsperf/blob/master/bench/k8s-dnsperf-bench.yaml

DNSPERF=dnsperf-2.3.2
apk add --update --no-cache --virtual deps wget g++ make bind-dev openssl-dev libxml2-dev libcap-dev json-c-dev krb5-dev protobuf-c-dev fstrm-dev \
  && apk add --update --no-cache bind libcrypto1.1 \
  && wget https://www.dns-oarc.net/files/dnsperf/$DNSPERF.tar.gz \
  && tar zxvf $DNSPERF.tar.gz \
  && cd $DNSPERF \
  && sh configure \
  && make \
  && strip ./src/dnsperf ./src/resperf \
  && make install

echo "kube-dns.kube-system.svc.cluster.local A" > records.txt
echo "echoserver.ops.svc.cluster.local A" > records.txt
dnsperf -l 10 \
        -s 10.140.0.53 \
        -T 20 \
        -c 20 \
        -q 10000 \
        -Q 10000 \
        -S 5 \
        -d records.txt

dnsperf -l 10 \
        -T 20 \
        -c 20 \
        -q 10000 \
        -Q 10000 \
        -S 5 \
        -d records.txt
  -l run for at most this many seconds
  -s the server
  -T the number of threads to run
  -c the number of clients to act as to query (default: 127.0.0.1)
  -q the maximum number of queries outstanding (default: 100)
  -Q limit the number of queries per second
  -S print qps statistics every N seconds
  -d the input data file (default: stdin)

2020-03-03

Open Google Chrome browser in Mac terminal

open -a "Google Chrome" "http://localhost:5601"

2020-03-02

Create a temporary pod to debug and kill itself after an hour

apiVersion: v1
kind: Pod
metadata:
  name: busybox1
  labels:
    app: busybox1
spec:
  containers:
  # - image: busybox
  - image: alpine:3.11
    command:
      - sleep
      - "3600"
    imagePullPolicy: IfNotPresent
    name: busybox
  restartPolicy: Never

DNS load testing in Alpine

apk add gcc g++ make libffi-dev openssl-dev git
git clone https://github.com/jedisct1/dnsblast.git
cd dnsblast && make
#./dnsblast [host] [times] [request per second]
./dnsblast kube-dns.kube-system 10000 1000
./dnsblast 127.0.0.1 10000 1000
  • The command above will break kube-dns.
  • There are 5 kube-dns pods, but only one is receiving request.
    • Caused by iptable and UDP.
dnsmasq I0302 08:47:01.002440       1 nanny.go:146[] dnsmasq[23]: Maximum number of concurrent DNS queries reached (max: 1500)
sidecar W0302 08:47:01.248582       1 server.go:64[] Error getting metrics from dnsmasq: read udp 127.0.0.1:37986->127.0.0.1:53: i/o timeout

GKE v1.13.x uses kube-dns rather than core-dns.

ref: https://cloud.google.com/kubernetes-engine/docs/release-notes#new_features_6

GKE is using kube- rather than core-dns. No idea why they are doing this.

Install gcc compiler in Alpine

ref: https://github.com/nange/blog/issues/3

apk add gcc g++ make libffi-dev openssl-dev

echo -n

https://linux.die.net/man/1/echo

-n
do not output the trailing newline

2020-02-27

Get GitHub user info

https://developer.github.com/v3/#authentication

curl -u "username" https://api.github.com/user
curl -H "Authorization: token $PAT" https://api.github.com/user

2020-02-26

Use CloudFlare WARP as VPN on Mac/PC

https://community.cloudflare.com/t/tutorial-how-to-use-cloudflare-warp-on-your-mac/129919?fbclid=IwAR3OlvJrv2EW3KoH3GlDA-gURM5BgPKiaP5RDjjlgBHyYpKWbryZzbrPDGw

WARP (CloudFlare VPN) is made from Wireguard. Therefore we can generate a Wirrguard config from CloudFlare and use it on PC.

Refresh/Clean CDN cache on Tencent Cloud

https://console.cloud.tencent.com/cdn/refresh

Just type what url you want to refresh.

You might have to verify by doing a request from a location with a Cloudflare edge

I tested it on https://tools.pingdom.com/

  • test in Tokyo
  • CloudFlare/Google CDN both have edges
  • GCS hosting need more DNS time: 40 ms

2020-02-24

CloudFlare worker - Can't resovle/find domain

Need to manully add this record to route worker. ref: https://community.cloudflare.com/t/a-record-name-for-worker/98841

Solution

Add an A record to 192.0.2.1

CloudFlare worker - how to handle SPA

I found there's 404 when I tried to refresh in other page like /faq.

ref: https://stackoverflow.com/questions/58432345/cloudflare-workers-spa-with-vuejs

options.mapRequestToAsset = req => {
    // First let's apply the default handler, which we imported from
    // '@cloudflare/kv-asset-handler' at the top of the file. We do
    // this because the default handler already has logic to detect
    // paths that should map to HTML files, for which it appends
    // `/index.html` to the path.
    req = mapRequestToAsset(req)

    // Now we can detect if the default handler decided to map to
    // index.html in some specific directory.
    if (req.url.endsWith('/index.html')) {
      // Indeed. Let's change it to instead map to the root `/index.html`.
      // This avoids the need to do a redundant lookup that we know will
      // fail.
      return new Request(`${new URL(req.url).origin}/index.html`, req)
    } else {
      // The default handler decided this is not an HTML page. It's probably
      // an image, CSS, or JS file. Leave it as-is.
      return req
    }
  }

2020-02-21

Multiple static IP in a load balancer

Steps:

  1. Manual create ip addresses.
  2. Assign ip addresses to load balancer frontend
  3. Use externalIPs instead of loadBalancerIP
    kind: Service
    apiVersion: v1
    metadata:
      name: dnsmasq
    spec:
      selector:
        name: dnsmasq
      type: LoadBalancer
      externalIPs:
      - a.a.a.a
      - a.a.a.b
      ports:
      - name: dnsmasq-udp
        port: 53
        protocol: UDP
        targetPort: dnsmasq-udp
      # loadBalancerIP: a.a.a.a
    

Testing HPA high memory

ref: https://github.com/feiskyer/kubernetes-handbook/blob/master/examples/hpa-memory.yaml

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: nginx-hpa
spec:
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: Deployment
    name: dnsmasq
  minReplicas: 1
  maxReplicas: 5
  metrics:
  - type: Resource
    resource:
      name: memory
      targetAverageUtilization: 60

and get in a container

$ kubectl exec -it dnsmasq-5964d6fdc-2ktt8 sh

generate high memory usage

$ yes | tr \\n x | head -c 100m | grep n

About Kubernetes HPA(Horizontal Pod Autoscaler)

ref: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale

2020-02-19

Use environment from parent process in Nginx(OpenResty)

在 nginx 讀取環境變數的正確方法:

  • 先在 root block export 變數
  • 使用 lua os.getenv("MY_ENV"))
    env MY_ENV;
    env PATH;
    http {
        server {
            location / {
                content_by_lua_block {
                    ngx.say(os.getenv("MY_ENV"));
                    ngx.say(os.getenv("PATH"));
                }
            }
        }
    }
    

cannot create an external load balancer with mix protocols

The Service "dnsmasq" is invalid: spec.ports: Invalid value: []core.ServicePort{core.ServicePort{Name:"dnsmasq", Protocol:"TCP", Port:53, TargetPort:intstr.IntOrString{Type:1, IntVal:0, StrVal:"dnsmasq"}, NodePort:0}, core.ServicePort{Name:"dnsmasq-udp", Protocol:"UDP", Port:53, TargetPort:intstr.IntOrString{Type:1, IntVal:0, StrVal:"dnsmasq-udp"}, NodePort:0}}: cannot create an external load balancer with mix protocols

2020-02-18

Try docker-compose health check

https://github.com/peter-evans/docker-compose-healthcheck

healthcheck:
  test: ["CMD-SHELL", "pg_isready -U postgres"]
  interval: 10s
  timeout: 5s
  retries: 5

Docker 更新後跳出 docker-credential-osxkeychain 想使用鑰匙圈 ci-db

https://github.com/docker/for-mac/issues/3805#issuecomment-518619953

Solution

Open ~/.docker/config.json

Set "credsStore":""

How to use cc-by-sa license

  • Plain text: https://creativecommons.org/licenses/by-sa/4.0/legalcode.txt

  • Image:

    <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-sa/4.0/88x31.png" /></a>
    
    [![](https://i.creativecommons.org/l/by-sa/4.0/88x31.png)](http://creativecommons.org/licenses/by-sa/4.0/)
    

ANSI - 輸出文字變色

echo -e "\e[1;31mHello\e[0m World"

Render a chart inside markdown with canvasjs

2020-02-15

Restart a kubernetes resource without down time and using same config(yaml)

Kubernetes >= 1.15

ref: https://github.com/kubernetes/kubernetes/issues/33664#issuecomment-497242094

Gracefully rolling restart deployment.

kubectl rollout restart deployment/my-sites --namespace=default

Run commnad without(ignoring) output

https://askubuntu.com/questions/474556/hiding-output-of-a-command

command > /dev/null 2>&1
command >& /dev/null

Example: Still show errors when command failed.

$ edho hi > /dev/null
zsh: command not found: edho
Don't show error even when command failed.
$ edho hi >& /dev/null

2020-02-13

在 docker-compose 中的容器互相溝通

service name 會被綁到 DNS,可以直接使用 service name 當作 host

version: '3'
services:
  redis:
    image: "redis:alpine"
    ports:
      - "6379:6379"
  celery:
    image: "celery:4.0.2"
    environment:
      - CELERY_BROKER_URL=redis://redis
  celery-2:
    image: "celery:4.0.2"
    environment:
      - CELERY_BROKER_URL=redis://redis
$ docker network ls
NETWORK ID          NAME                        DRIVER              SCOPE
01681ec52fea        celery_default              bridge              local
$ docker exec -it celery_celery_1 bash
user@dcd8cf4a9d04:~$ ping celery-2
PING celery-2 (192.168.0.4): 56 data bytes
64 bytes from 192.168.0.4: icmp_seq=0 ttl=64 time=0.162 ms
64 bytes from 192.168.0.4: icmp_seq=1 ttl=64 time=0.223 ms
^C--- celery-2 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.162/0.193/0.223/0.031 ms
user@dcd8cf4a9d04:~$ ping celery-3
ping: unknown host

mkdocs minify html got error

mkdocs.yaml

plugins:
  - minify:
      minify_html: true

Bug

    print "htmlmin option " + key + " not recognized"
                        ^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print("htmlmin option " + key + " not recognized")?

Solution

ref: https://github.com/byrnereese/mkdocs-minify-plugin/issues/8

Upgrade mkdocs-minify-plugin>= 0.2.3


Last update: December 22, 2020

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