It doesn't seem to work with the described workaround. When i update jenkins to version 2.275, and add the EntryPoint Cmd "${JAVA_EXE} ${JVM_ARGS} -jar ${FS_DIR}/${JAR_NAME} -noReconnect -noKeepAlive -agentLog ${FS_DIR}/agent.log", i get the following content in the logfile of the jenkins master:
2021-01-18 23:20:35.621+0000 [id=33] INFO c.n.j.plugins.docker.DockerCloud#provision: Will provision 'cid-jenkins-debian-slave:latest', for label: 'lcl_cid-jenkins-debian-slave', in cloud: 'lcl-slave-cloud'
2021-01-18 23:20:35.625+0000 [id=238] INFO c.n.j.p.docker.DockerTemplate#doProvisionNode: Trying to run container for image "cid-jenkins-debian-slave:latest"
2021-01-18 23:20:35.626+0000 [id=238] INFO c.n.j.p.docker.DockerTemplate#doProvisionNode: Trying to run container for node lcl_cid-jenkins-debian-slave-0000qbpplgfpg from image: cid-jenkins-debian-slave:latest
2021-01-18 23:20:35.627+0000 [id=33] INFO h.s.NodeProvisioner$StandardStrategyImpl#apply: Started provisioning Image of cid-jenkins-debian-slave:latest from lcl-slave-cloud with 1 executors. Remaining excess workload: 0
2021-01-18 23:20:35.717+0000 [id=238] INFO c.n.j.p.docker.DockerTemplate#doProvisionNode: Started container ID 8887888b049d2a2c8b01ceaa7e0f1737bc81ae7d96a9460fe76eb3b60c2f0ffa for node lcl_cid-jenkins-debian-slave-0000qbpplgfpg from image: cid-jenkins-debian-slave:latest
2021-01-18 23:20:45.613+0000 [id=36] INFO hudson.slaves.NodeProvisioner#lambda$update$6: Image of cid-jenkins-debian-slave:latest provisioning successfully completed. We have now 6 computer(s)
2021-01-18 23:20:45.633+0000 [id=36] INFO c.n.j.plugins.docker.DockerCloud#canAddProvisionedSlave: Provisioning 'cid-jenkins-debian-slave:latest' on 'lcl-slave-cloud'; Total containers: 5 (of 6)
As you can see, the container will be started 6 times, but nothing happens. I tried to replace the variables by fixed values <- same result. There no logs written in the slave container. Exact the same configuration (set statically with casc.yml on newly created containers, so its definitivly the same config) work with a Jenkins 2.265 version without setting the EntryPoint cmd). Do you have any idea? Do i something wrong?
The original descripiton said "no builds are possible now" - that was incorrect ... builds are still possible; the problem is that the default settings are no longer viable (if you override them, it can still work).
See this comment in docker-plugin issue 818 for details of the workaround.