Is it possible to actual run the docker steps?

Building docker image for runtime null
[Pipeline] sh
[job] Running shell script
+ docker build -t tests:null -f Dockerfile.tests .
/tmp/jenkinsTests.tmp/jenkins8996889882339540707test/workspace/job@tmp/durable-57fedee8/script.sh: 2: /tmp/jenkinsTests.tmp/jenkins8996889882339540707test/workspace/job@tmp/durable-57fedee8/script.sh: docker: not found
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Tests Execution)
...
...
...
ERROR: script returned exit code 127
Finished: FAILURE

[marcellodesales]

@ndeloof @schnatterer I actually got it to work following the suggestions from https://forums.docker.com/t/using-docker-in-a-dockerized-jenkins-container/322. I could get it to work to just run a container with the following volumes:

• Mount the /var/run/docker.sock
• Mount the docker command

Solution

• I built the image locally and tagged as marcellodesales/jenkinsfile-runner
• Running a container and mounting the volumes described

This is actually an acceptable solution for my case using Docker for Mac to support development of the Pipeline.

$ docker run -v $(pwd):/workspace  \
      -v /var/run/docker.sock:/var/run/docker.sock \
      -v $(which docker):$(which docker) marcellodesales/jenkinsfile-runner
Started
Running in Durability level: PERFORMANCE_OPTIMIZED
[
...
...
[Pipeline] [Validate Test] }
[Pipeline] // parallel
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Build Test Image)
[Pipeline] script
[Pipeline] {
[Pipeline] }
[Pipeline] // script
[Pipeline] echo
Building docker image for tests from build stage null
[Pipeline] sh
[job] Running shell script
+ docker build -t tests:null -f Dockerfile --target builder .
Sending build context to Docker daemon  13.75MB
Step 1/9 : FROM maven:3.2.5-jdk-8 as builder
 ---> 95dd59c15f5d
Step 2/9 : MAINTAINER [e-mail]
 ---> Using cache
 ---> e4edaeb48381
Step 3/9 : ADD ./pom.xml /opt/build/pom.xml
 ---> Using cache
 ---> 2ca95e0b276e
Step 4/9 : ADD ./settings.xml /opt/build/settings.xml
 ---> Using cache
 ---> 1c52ecafca2b
Step 5/9 : WORKDIR  /opt/build/
 ---> Using cache
 ---> e2f5d1a6467f
Step 6/9 : RUN mvn -s settings.xml -B -e -C -T 1C org.apache.maven.plugins:maven-dependency-plugin:3.0.2:go-offline
 ---> Using cache
 ---> 9212f3bd2e5b
Step 7/9 : ADD ./src /opt/build/src
 ---> f7e2cc9f9aa6
Step 8/9 : RUN mvn -s settings.xml install -P embedded -Dmaven.test.skip=true -B -e -o -T 1C verify
 ---> Running in 52b96eb70b06
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO]
[INFO] Using the MultiThreadedBuilder implementation with a thread count of 4
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building spring-cloud-config-server 1.1.6-SNAPSHOT
[INFO] ---------------------------------------------------
...
...
...
[INFO] --- maven-failsafe-plugin:2.20.1:integration-test (integration-test) @ spring-cloud-config-server ---
[INFO] Tests are skipped.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 27.438 s (Wall Clock)
[INFO] Finished at: 2018-04-23T21:02:49+00:00
[INFO] Final Memory: 46M/216M
[INFO] ------------------------------------------------------------------------
Removing intermediate container 52b96eb70b06
 ---> bbefce46d3bd
Step 9/9 : CMD mvn -s settings.xml -Dtest="!*IT,!*IntegrationTest" -P jacoco test
 ---> Running in aa7ab08da632
Removing intermediate container aa7ab08da632
 ---> a65a5a81ee21
Successfully built a65a5a81ee21
Successfully tagged tests:null
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Tests Execution)
[Pipeline] parallel
[Pipeline] [Execute Unit Tests] { (Branch: Execute Unit Tests)
[Pipeline] [Execute Integration Tests] { (Branch: Execute Integration Tests)
[Pipeline] [Execute Unit Tests] stage

[ndeloof]

I can’t see any reason the jenkinsfile-runner could not run docker steps, it just need docker command line available in the current node, i.e local machine running jenkinsfile-runner.

Based on your comment :

Could we somehow mount the docker socket and mount or install the client binary into jenkinsfile-runner?

it sounds like you use jenkinsfile-runner from a docker image, not running directly as a CLI tool. Doing so you indeed need to customize the docker image to have docker CLI installed and grant access to docker infrastructure.