update jenkins timezone

There many ways to update jenkins timezone

Verify:

cat /etc/timezone
cat ls -ltr /etc/localtime
date

Centos/Redhat:

#update /etc/sysconfig/jenkins

#JENKINS_JAVA_OPTIONS="-Dorg.apache.commons.jelly.tags.fmt.timeZone=Asia/Calcutta"
#JENKINS_JAVA_OPTIONS="-Duser.timezone=Asia/Calcutta"

Debian/ubuntu :

#update /etc/default/jenkins

JAVA_ARGS="-Dorg.apache.commons.jelly.tags.fmt.timeZone=Asia/Calcutta"
JAVA_ARGS="-Duser.timezone=Asia/Calcutta"

Jenkins script console:


System.setProperty('user.timezone', 'Asia/Calcutta')
System.setProperty('org.apache.commons.jelly.tags.fmt.timeZone', 'Asia/Calcutta')

Check tcp port with BASH and CURL

WHY?
– If telnet command is not present on system
– Easy to use

BASH:

ECHO:

#1
echo > /dev/tcp/192.168.0.183/22

#2
echo > /dev/tcp/192.168.0.183/22 && echo "open"

#3
echo > /dev/tcp/192.168.0.183/22 && echo "open" || echo "close"

#4
(echo > /dev/tcp/192.168.0.183/22)  > /dev/null 2>&1 && echo "open" || echo "close"

CAT:

cat < /dev/tcp/192.168.0.183/22

CURL:

curl -v telnet://192.168.0.183:22
curl -v telnet://hackfi.initedit.com:80

Install metric server in kubernetes

WHY?
– Get node CPU/RAM usages
– Can create Horizontal Pod Autoscaler (HPA)
– Light weight

git clone https://github.com/kubernetes-sigs/metrics-server.git
  • Edit metrics-server/manifests/base/deployment.yaml and add below lines to args
args:
          - --cert-dir=/tmp
          - --secure-port=4443
          - --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
          - --kubelet-use-node-status-port #Deprecated metrics-server:v0.3.7
          - --kubelet-insecure-tls

kubectl apply -f metrics-server/manifests/base
  • To get node metrics run kubectl get top node

Jenkins skip stages using git branch name regex


def git_url = 'https://github.com/initedit/simple-storage-solution.git'
def git_branch = 'master'

pipeline
{
    agent
    {
        label 'master'
    }

    stages
    {
        stage('skip1')
        {
            when {
            expression {
                        echo git_branch
                        isDev = !(git_branch =~ /^dev*([a-zA-Z0-9]*)/)
                        return isDev
                       }
            }
            steps{
                   echo "if dev branch it will skip"
               }
        
        }
    }
}

Regex:
^dev*([a-zA-Z0-9]* = Start with dev
dev*([a-zA-Z0-9]* = contains dev

More : https://e.printstacktrace.blog/groovy-regular-expressions-the-definitive-guide/

Jenkins pipeline timeout and buildDiscarder – best practice

1. Add timeout – To stop pipeline run in infinitely
2. Add build Discard – To stop build to consume disk space

pipeline 
{

    agent { label 'master' }

    options {
        buildDiscarder(logRotator(numToKeepStr: '5'))
        timeout(time: 10, unit: 'SECONDS')
        timestamps()
    }

    stages {
        stage('sleep'){
            steps {
                    sh '''
                    echo sleeping
                    sleep 60
                    '''
                }
            }        
        }
    }

Elastic APM monitoring for javascript app on kubernetes

1.apm-server.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: apm-deployment
  labels:
    app: apm-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: apm-deployment
  template:
    metadata:
      labels:
        app: apm-deployment
        env: prod
    spec: 
      containers:
        - name: apm-deployment
          image: "elastic/apm-server:7.9.0"
          imagePullPolicy: IfNotPresent
          env:
          - name: REGISTRY_STORAGE_DELETE_ENABLED
            value: "true"
          volumeMounts:
          - name: apm-server-config
            mountPath: /usr/share/apm-server/apm-server.yml
            subPath: apm-server.yml    
          ports:
            - containerPort: 8200
      volumes:
        - name: apm-server-config
          configMap:
            name: apm-server-config


---
kind: Service
apiVersion: v1
metadata:
  name: apm-deployment-svc
  labels:
    app: apm-deployment-svc
spec:
  type: NodePort
  ports:
    - name: http
      port: 8200
      protocol: TCP
      nodePort: 30010
  selector:
    app: apm-deployment

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: apm-server-config
  labels:
    app: apm-server
data:
  apm-server.yml: |-
    apm-server:
      host: "0.0.0.0:8200"
      rum:
        enabled: true  
    output.elasticsearch:
      hosts: elasticsearch-service:9200

Note:
1. Replace elasticsearch host as per your config
2. Only RUM js module is enabled

2. Add below code to your js file which is called in everyfile for eg. index.html

<script src="elastic-apm-rum.umd.min.js" crossorigin></script>
<script>
  elasticApm.init({
    serviceName: 'test-app1',
    serverUrl: 'http://192.168.0.183:30010',
  })
</script>

<body>
    This is test-app1
</body>

Note:
1. Replace serverUrl
2. Download elastic-apm-rum.umd.min.js from github

3. Kibana dashboard for APM

We can also monitor other languages apps performance

Simple cicd pipeline in Gitlab with runner

1.Install gitlab runner on centos7

wget https://gitlab-runner-downloads.s3.amazonaws.com/latest/rpm/gitlab-runner_amd64.rpm

rpm -ivh gitlab-runner_amd64.rpm

systemctl status gitlab-runner

More : https://docs.gitlab.com/runner/install/

2.Get Gitlab URL and token for runner

https://gitlab.com/<username>/<project_name> > setting > CI / CD > Runners

Note: This token has been revoked. you will have different token

3.Register Runner with gitlab-runner register command as below

4.Create .gitlab-ci.yml in your gitproject root directory

stage1:
  tags:
  - ci
  script:
    - echo stage 1

stage2:
  tags:
  - ci
  script:
    - echo stage 2

tags: it’s should be same as we used in runner registration

prometheus blackbox exporter in Kubernetes

prometheus-blackbox.yml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
spec:
  replicas: 1
  selector:
    matchLabels:
      app: prometheus-blackbox-exporter
  template:
    metadata:
      labels:
        app: prometheus-blackbox-exporter
    spec:
      restartPolicy: Always
      containers:
        - name: blackbox-exporter
          image: "prom/blackbox-exporter:v0.15.1"
          imagePullPolicy: IfNotPresent
          args:
            - "--config.file=/config/blackbox.yaml"
          ports:
            - containerPort: 9115
          volumeMounts:
            - mountPath: /config
              name: prometheus-config
      volumes:
        - name: prometheus-config
          configMap:
            name: prometheus-blackbox-exporter

---
kind: Service
apiVersion: v1
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
spec:
  type: ClusterIP
  ports:
    - name: http
      port: 9115
      protocol: TCP
  selector:
    app: prometheus-blackbox-exporter

---

apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
data:
  blackbox.yaml: |
    modules:
      http_2xx:
        http:
          no_follow_redirects: false
          preferred_ip_protocol: ip4
          valid_http_versions:
          - HTTP/1.1
          - HTTP/2
          valid_status_codes: []
        prober: http
        timeout: 5s

2. in prometheus update prometheus.yml file as below

3. Prometheus query

probe_http_status_code{job="web1"}