Issue
I have a mysql image with a prepolutated schema, below I share the setup files.
My dockerfile:
FROM mysql:8.0.31 as builder
# That file does the DB initialization but also runs mysql daemon, by removing the last line it will only init
RUN ["sed", "-i", "s/exec \"$@\"/echo \"not running $@\"/", "/usr/local/bin/docker-entrypoint.sh"]
# needed for intialization
ENV MYSQL_ROOT_PASSWORD=test
COPY ./sql-scripts /docker-entrypoint-initdb.d/
# Need to change the datadir to something else that /var/lib/mysql because the parent docker file defines it as a volume.
# https://docs.docker.com/engine/reference/builder/#volume :
# Changing the volume from within the Dockerfile: If any build steps change the data within the volume after
# it has been declared, those changes will be discarded.
RUN ["/usr/local/bin/docker-entrypoint.sh", "mysqld", "--datadir", "/initialized-db"]
FROM mysql:8.0.31
COPY --from=builder /initialized-db /var/lib/mysql
My pod template yaml:
apiVersion: v1
kind: Pod
metadata:
labels:
label: 'backend'
spec:
shareProcessNamespace: true
containers:
- name: "maven"
image: maven:3.6.3-openjdk-11
resources:
requests:
memory: "2Gi"
cpu: "2"
limits:
memory: "10Gi"
cpu: "10"
command: [ sleep ]
args: [ 1h ]
securityContext:
capabilities:
add:
- SYS_PTRACE
- name: mysql
image: myDockerRegistry/mysql8-integration-test:v5
env:
- name: MYSQL_USER
value: test
- name: MYSQL_PASSWORD
value: test
- name: MYSQL_ROOT_PASSWORD
value: test
securityContext:
capabilities:
add:
- SYS_PTRACE
My pipeline:
pipeline {
agent {
kubernetes {
yaml libraryResource('pod-templates/backend.yaml')
}
}
stages { ... }
}
The above setup works fine, but I want to use a dynamic PVC for the workspace, then I add the following line to my pipeline after the pod template.
workspaceVolume dynamicPVC(accessModes: 'ReadWriteOnce',requestsSize: "10Gi", storageClassName: 'premium-rwo')
But I have to add securityContext to my pod template so jenkins will able to mount the PVC in the agent:
spec:
securityContext:
runAsUser: 1000
runAsGroup: 1000
fsGroup: 1000
With those changes the pod start and the volume is mounted correctly, but the mysql container doesn't work. This is the error log:
2022-11-03 09:33:25+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
'/var/lib/mysql/mysql.sock' -> '/var/run/mysqld/mysqld.sock'
2022-11-03T09:33:25.839933Z 0 [Warning] [MY-011068] [Server] The syntax '--skip-host-cache' is deprecated and will be removed in a future release. Please use SET GLOBAL host_cache_size=0 instead.
2022-11-03T09:33:25.842508Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.31) starting as process 13
2022-11-03T09:33:25.845263Z 0 [Warning] [MY-010122] [Server] One can only use the --user switch if running as root
mysqld: File './binlog.index' not found (OS errno 13 - Permission denied)
2022-11-03T09:33:25.845867Z 0 [ERROR] [MY-010119] [Server] Aborting
2022-11-03T09:33:25.846078Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.31) MySQL Community Server - GPL.
I asume is something related with root rights in the mysql container, but is weird because the official image runs perfectly.
Finally this is the raw yaml generated after inject the jenkins agent:
apiVersion: v1
kind: Pod
metadata:
annotations:
buildUrl: >-
http://jenkins.jenkins.svc.cluster.local:8080/job/LegacyProjects/job/my-project/job/k8s-test/79/
runUrl: job/LegacyProjects/job/my-project/job/k8s-test/79/
labels:
label: backend
jenkins/jenkins-jenkins-agent: 'true'
jenkins/label-digest: 4581eadfdfcb3d0141b8e8727b53b2ff9a3575ec
jenkins/label: LegacyProjects_my-project_k8s-test_79-xgtxd
name: my-project-k8s-test-79-xgtxd-2xw2r-8wj64
namespace: jenkins
spec:
containers:
- args:
- 1h
command:
- sleep
image: 'maven:3.6.3-openjdk-11'
name: maven
resources:
limits:
memory: 10Gi
cpu: '10'
requests:
memory: 2Gi
cpu: '2'
securityContext:
capabilities:
add:
- SYS_PTRACE
volumeMounts:
- mountPath: /home/jenkins/agent
name: workspace-volume
readOnly: false
- env:
- name: MYSQL_USER
value: test
- name: MYSQL_PASSWORD
value: test
- name: MYSQL_ROOT_PASSWORD
value: test
image: 'myDockerRegistry/mysql8-integration-test:v5'
name: mysql
securityContext:
capabilities:
add:
- SYS_PTRACE
volumeMounts:
- mountPath: /home/jenkins/agent
name: workspace-volume
readOnly: false
- env:
- name: JENKINS_SECRET
value: '********'
- name: JENKINS_TUNNEL
value: 'jenkins-agent.jenkins.svc.cluster.local:50000'
- name: JENKINS_AGENT_NAME
value: my-project-k8s-test-79-xgtxd-2xw2r-8wj64
- name: JENKINS_NAME
value: my-project-k8s-test-79-xgtxd-2xw2r-8wj64
- name: JENKINS_AGENT_WORKDIR
value: /home/jenkins/agent
- name: JENKINS_URL
value: 'http://jenkins.jenkins.svc.cluster.local:8080/'
image: 'jenkins/inbound-agent:4.11-1-jdk11'
name: jnlp
resources:
limits: {}
requests:
memory: 256Mi
cpu: 100m
volumeMounts:
- mountPath: /home/jenkins/agent
name: workspace-volume
readOnly: false
nodeSelector:
kubernetes.io/os: linux
restartPolicy: Never
securityContext:
fsGroup: 1000
runAsGroup: 1000
runAsUser: 1000
shareProcessNamespace: true
volumes:
- name: workspace-volume
persistentVolumeClaim:
claimName: pvc-workspace-my-project-test-79-xgtxd-2xw2r-8wj64
readOnly: false
Any help will be appreciated
Solution
COPY
command by default works only as root user, you should specify --chown=1000:1000
flag to that command to set the correct user and group (in your case - it's user with uid and gid 1000, which is specified in securityContext), see https://stackoverflow.com/a/44766666 and https://docs.docker.com/engine/reference/builder/#copy for more details
While your use case might require pre-building image with database, consider running official mysql image as db, and your application with init container with liquibase/flyway or other (even in-built) database migration toolkit, which might be a more portable solution in a long run
Answered By - Andrew
Answer Checked By - David Marino (JavaFixing Volunteer)