docker commands failing in jenkins shell step

Question

I have installed docker on my RHEL slaves

and have given permissions to "tomcat" user

sudo usermod -aG docker tomcat

I am able to run this command "docker run hello-world" as tomcat user on the box directly, but when I am running the same through Jenkins its failing

Running Prebuild steps
[docker-test] $ /bin/sh -xe /tmp/jenkins5880049234473840635.sh
+ whoami
tomcat
+ docker -v
Docker version 1.12.6, build 96d83a5/1.12.6
+ docker run hello-world
/usr/bin/docker-current: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See '/usr/bin/docker-current run --help'.
Build step 'Execute shell' marked build as failure

Answer 1

you give the permission to "tomcat" user.. Is it your jenkins ssh user? (user used to connect on slave?) if yes, you must restart your jenkins (i had this problem)

else you must give permission to the user used to connect on slave and restart your jenkins