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Kubernetes Jenkins slave with odd resource numbers

1/31/2020

I'm running Jenkins pod with helm charts and having weird logs when starting jenkins jobs. The requested resources and limits are seems to be in default state - compared to what I set in values.

helm install stable/jenkins --name jenkins -f jenkins.yaml

And after creating and running random job from UI

Agent jenkins-agent-mql8q is provisioned from template Kubernetes Pod Template
---
apiVersion: "v1"
kind: "Pod"
metadata:
  annotations: {}
  labels:
    jenkins/jenkins-slave: "true"
    jenkins/label: "jenkins-jenkins-slavex"
  name: "jenkins-agent-mql8q"
spec:
  containers:
  - args:
    - "********"
    - "jenkins-agent-mql8q"
    env:
    - name: "JENKINS_SECRET"
      value: "********"
    - name: "JENKINS_TUNNEL"
      value: "jenkins-agent:50000"
    - name: "JENKINS_AGENT_NAME"
      value: "jenkins-agent-mql8q"
    - name: "JENKINS_NAME"
      value: "jenkins-agent-mql8q"
    - name: "JENKINS_AGENT_WORKDIR"
      value: "/home/jenkins/agent"
    - name: "JENKINS_URL"
      value: "http://jenkins:8080/"
    image: "jenkins/jnlp-slave:3.27.1"
    imagePullPolicy: "IfNotPresent"
    name: "jnlp"
    resources:
      limits:
        memory: "2Gi"
        cpu: "2"
      requests:
        memory: "1Gi"
        cpu: "1"

And my helm values is

master:
(...)
  resources:
    requests:
      cpu: "1"
      memory: "1Gi"
    limits:
      cpu: "3"
      memory: "3Gi"
agent:
  resources:
    requests:
      cpu: "2"
      memory: "2Gi"
    limits:
      cpu: "4"
      memory: "3Gi"

Any idea why it spawns agents with default 1cpu/1Gi to 2cpu/2Gi

-- CptDolphin

jenkins

kubernetes

kubernetes-helm

1 Answer

2/5/2020

I've reproduced your scenario, I will explain how that works for me. I'm using GKE with Kubernetes 1.15.3 and HELM 2.16.1.

I've downloaded the helm chart to my local machine, and decompress the file to customize the value.yaml:

$ helm fetch stable/jenkins
$ tar xzvf jenkins-1.9.16.tgz

In jenkins folder, edit the lines 422-427 from values.yaml file.

agent:
...
    requests:
      cpu: "2"
      memory: "2Gi"
    limits:
      cpu: "4"
      memory: "3Gi"
...

This will configure the agent container to spawn with the specified resources.

Perform other changes in file if you desire, for this example I'll let with default values.

Install helm chart:

helm install jenkins/ -n jenkins

After installed, follow the instructions on screen to access the jenkins console.

To verify if the agents will start with configured resources, let's create a new job using a simple shell command.

New Item > Freestyle project

In Job configuration, select "Execute shell" above the section "Build" in dropdown list. Type any linux command as id, ls, uname -a etc...

Save and trigger Build Now button.

Verify in kubernetes for the new containers, in this case a new agent container is named with default-6w3fq

See pod description:

kubectl describe pod default-6w3fq

Name:         default-6w3fq
...
IP:           
Containers:
  jnlp:
    Image:      jenkins/jnlp-slave:3.27-1
...
    Limits:
      cpu:     4
      memory:  3Gi
    Requests:
      cpu:     2
      memory:  2Gi
...

You could wait for the job completion and see the job logs instead to use kubectl command.

I've tried to deploy with default values, and upgrade the helm chart with new values values... nothing happened. That worked when I ran upgrade with --force flag: helm upgrade jenkins jenkins/ --force

--force - force resource updates through a replacement strategy

References: https://helm.sh/docs/helm/helm_upgrade/ https://github.com/helm/charts/tree/master/stable/jenkins

-- KoopaKiller

Source: StackOverflow

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Kubernetes Jenkins slave with odd resource numbers

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