Why when using Jenkins dockerfile agent does it ru

Question

I have a pretty standard Dockerfile:

FROM python:3.6.5
WORKDIR /src
COPY . /src

... install and configure things ...

and a pretty standard Jenkinsfile

pipeline {
    agent none

    stages {
        stage('Test') {
            agent { dockerfile true }
            steps {
                dir('/src') {
                    sh 'pwd'  // any command
                }
            }
        }
    }
}

However when this is run in Jenkins (I should mention I'm currently testing using a local Jenkins instance in a docker container) the Dockerfile builds successfully but when Jenkins attempts to run the step I get the following output:

[Pipeline] withDockerContainer
Jenkins seems to be running inside container aaee62f2a28e29b94c13fcdc08c1a82ef7baed48beabe54579db07b2fbd26b23
$ docker run -t -d -u 1000:1000 -w "/var/jenkins_home/workspace/My Project" --volumes-from aaee62f2a28e29b94c13fcdc08c1a82ef7baed48beabe54579db07b2fbd26b23 -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** -e ******** 12724611f0bf2363c9eee7288654e43eca2aabaf cat
$ docker top 4e29bc102d8f4e6b4ffc142fc06eb706e95b00fa6190b2927f4f79f0cfa53af5 -eo pid,comm
[Pipeline] {
[Pipeline] withEnv
[Pipeline] {
[Pipeline] dir
Running in /src
[Pipeline] {
[Pipeline] sh
[Pipeline] }
[Pipeline] // dir
[Pipeline] }
[Pipeline] // withEnv
[Pipeline] }
$ docker stop --time=1 4e29bc102d8f4e6b4ffc142fc06eb706e95b00fa6190b2927f4f79f0cfa53af5
$ docker rm -f 4e29bc102d8f4e6b4ffc142fc06eb706e95b00fa6190b2927f4f79f0cfa53af5

which is not expected, and when the step is "finished" there is the following failure message:

java.nio.file.AccessDeniedException: /src
    at sun.nio.fs.UnixException.translateToIOException(UnixException.java:84)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
    at sun.nio.fs.UnixFileSystemProvider.createDirectory(UnixFileSystemProvider.java:384)
    at java.nio.file.Files.createDirectory(Files.java:674)
    at java.nio.file.Files.createAndCheckIsDirectory(Files.java:781)
    at java.nio.file.Files.createDirectories(Files.java:767)
    at hudson.FilePath.mkdirs(FilePath.java:3273)
    at hudson.FilePath.access$1300(FilePath.java:213)
    at hudson.FilePath$Mkdirs.invoke(FilePath.java:1254)
    at hudson.FilePath$Mkdirs.invoke(FilePath.java:1250)
    at hudson.FilePath.act(FilePath.java:1078)
    at hudson.FilePath.act(FilePath.java:1061)
    at hudson.FilePath.mkdirs(FilePath.java:1246)
    at org.jenkinsci.plugins.durabletask.FileMonitoringTask$FileMonitoringController.<init>(FileMonitoringTask.java:181)
    at org.jenkinsci.plugins.durabletask.BourneShellScript$ShellController.<init>(BourneShellScript.java:221)
    at org.jenkinsci.plugins.durabletask.BourneShellScript$ShellController.<init>(BourneShellScript.java:210)
    at org.jenkinsci.plugins.durabletask.BourneShellScript.launchWithCookie(BourneShellScript.java:131)
    at org.jenkinsci.plugins.durabletask.FileMonitoringTask.launch(FileMonitoringTask.java:99)
    at org.jenkinsci.plugins.workflow.steps.durable_task.DurableTaskStep$Execution.start(DurableTaskStep.java:305)
    at org.jenkinsci.plugins.workflow.cps.DSL.invokeStep(DSL.java:268)
    at org.jenkinsci.plugins.workflow.cps.DSL.invokeMethod(DSL.java:176)
    at org.jenkinsci.plugins.workflow.cps.CpsScript.invokeMethod(CpsScript.java:122)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
    at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1213)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
    at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:42)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:157)
    at org.kohsuke.groovy.sandbox.GroovyInterceptor.onMethodCall(GroovyInterceptor.java:23)
    at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onMethodCall(SandboxInterceptor.java:155)
    at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:155)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:159)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:129)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:129)
    at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.methodCall(SandboxInvoker.java:17)
    at WorkflowScript.run(WorkflowScript:23)
    at ___cps.transform___(Native Method)
    at com.cloudbees.groovy.cps.impl.ContinuationGroup.methodCall(ContinuationGroup.java:57)
    at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.dispatchOrArg(FunctionCallBlock.java:109)
    at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.fixArg(FunctionCallBlock.java:82)
    at sun.reflect.GeneratedMethodAccessor143.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
    at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
    at com.cloudbees.groovy.cps.Next.step(Next.java:83)
    at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:174)
    at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:163)
    at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:129)
    at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:268)
    at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:163)
    at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$101(SandboxContinuable.java:34)
    at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.lambda$run0$0(SandboxContinuable.java:59)
    at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.GroovySandbox.runInSandbox(GroovySandbox.java:136)
    at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:58)
    at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:182)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:332)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$200(CpsThreadGroup.java:83)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:244)
    at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:232)
    at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:131)
    at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
    at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Finished: FAILURE

The problem appears to be with this line: docker run -t -d -u 1000:1000 there is no user with UID 1000 on the container built by the Dockerfile, commands are run by root and therefore with the directory change to /src the "user" that jenkins specifies has no access to the files.

How do you prevent Jenkins from trying to use -u 1000:1000 by default? or what steps should I take to resolve this issue. I could in theory add a chmod 777 into the dockerfile but this seems like an ugly workaround

Update:

I added RUN chmod -R 777 /src to my Dockerfile but the issue remains. If I run the container manually from inside the docker Jenkins container:

docker run -it -u 1000:1000 -w "/var/jenkins_home/workspace/My Project" --volumes-from aaee62f2a28e29b94c13fcdc08c1a82ef7baed48beabe54579db07b2fbd26b23 12724611f0bf2363c9eee7288654e43eca2aabaf /bin/bash

and cd /src I have access to the files and can do e.g. touch newfile without issues. The java.nio.file.AccessDeniedException: /src still appears in the logs though

Answer 1

It seems that you can override/pass docker arguments according to this, so you might try this in order to override the default using uid/gid

args: A string. Runtime arguments to pass to docker run.

This option is valid for docker and dockerfile.

agent {
    dockerfile {
        args '-u 0:0' // or try to make it -u root
    }
}