How to solve Docker permission error when trigger by Jenkins

Question

My Jenkins is not run in Docker container, just tradional install to VPS. I got the following error when executing a simple test project. I am using Ubuntu 14, java 7, and stable Jenkins. I tried all methods I can find on google, but can't get it work.

I am trying to execute this shell

docker build --pull=true -t nick/hello-jenkins:$GIT_COMMIT . 

After code change.

Here is error:

Got permission denied while trying to connect to the Docker daemon socket at unix: .... 

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Started by user nicolas xu Building in workspace /var/lib/jenkins/workspace/hello-Jenkins  > git rev-parse --is-inside-work-tree # timeout=10 Fetching changes from the remote Git repository  > git config remote.origin.url https://github.com/nicolasxu/hello-nick-jenkins.git # timeout=10 Fetching upstream changes from https://github.com/nicolasxu/hello-nick-jenkins.git  > git --version # timeout=10  > git fetch --tags --progress https://github.com/nicolasxu/hello-nick-jenkins.git +refs/heads/*:refs/remotes/origin/*  > git rev-parse refs/remotes/origin/master^{commit} # timeout=10  > git rev-parse refs/remotes/origin/origin/master^{commit} # timeout=10 Checking out Revision d94ae21a8a2cf58ffc790dcad15bd851fb17df5a (refs/remotes/origin/master)  > git config core.sparsecheckout # timeout=10  > git checkout -f d94ae21a8a2cf58ffc790dcad15bd851fb17df5a  > git rev-list d94ae21a8a2cf58ffc790dcad15bd851fb17df5a # timeout=10 [hello-Jenkins] $ /bin/sh -xe /tmp/hudson5076309502904684976.sh + docker build --pull=true -t nick/hello-jenkins:d94ae21a8a2cf58ffc790dcad15bd851fb17df5a . Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.27/build?buildargs=%7B%7D&cachefrom=%5B%5D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&labels=%7B%7D&memory=0&memswap=0&networkmode=default&pull=1&rm=1&shmsize=0&t=nick%2Fhello-jenkins%3Ad94ae21a8a2cf58ffc790dcad15bd851fb17df5a&ulimits=null: dial unix /var/run/docker.sock: connect: permission denied Build step 'Execute shell' marked build as failure Finished: FAILURE 

I can run 'docker' in console as root no problem, why jenkins can't try a shell command which runs 'docker'? What is going on? Totally confused.......

Answer 1

In your VPS server terminal, do this to add your jenkins user to the docker group:

sudo usermod -aG docker jenkins 

Then restart your jenkins server to refresh the group.

Take into account any security issue that this could produce:

Warning: The docker group grants privileges equivalent to the root user. For details on how this impacts security in your system, see Docker Daemon Attack Surface.

Refer to the docs

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Edit (mentioned by @iger): Just make sure to restart the Jenkins from command-line (i.e. sudo service jenkins restart), but not through the rest endpoint (http:///restart)