Access to Docker Unix socket is broken

[ruskii22]

Jenkins and plugins versions report

There are only two Jenkins: 2.430
OS: Linux - 5.15.0-89-generic
Java: 17.0.8.1 - Eclipse Adoptium (OpenJDK 64-Bit Server VM)

ant:497.v94e7d9fffa_b_9
antisamy-markup-formatter:162.v0e6ec0fcfcf6
apache-httpcomponents-client-4-api:4.5.14-208.v438351942757
apache-httpcomponents-client-5-api:5.2.3-1.0
authentication-tokens:1.53.v1c90fd9191a_b_
bootstrap5-api:5.3.2-2
bouncycastle-api:2.29
branch-api:2.1135.v8de8e7899051
build-timeout:1.31
caffeine-api:3.1.8-133.v17b_1ff2e0599
checks-api:2.0.2
cloud-stats:320.v96b_65297a_4b_b_
cloudbees-folder:6.858.v898218f3609d
commons-lang3-api:3.13.0-62.v7d18e55f51e2
commons-text-api:1.11.0-94.v3e1f4a_926e49
configuration-as-code:1746.vf1673cfe690a
credentials:1309.v8835d63eb_d8a_
credentials-binding:642.v737c34dea_6c2
display-url-api:2.200.vb_9327d658781
docker-build-step:2.10
docker-commons:439.va_3cb_0a_6a_fb_29
docker-java-api:3.3.4-86.v39b_a_5ede342c
docker-plugin:1.5
docker-workflow:572.v950f58993843
durable-task:523.va_a_22cf15d5e0
echarts-api:5.4.3-1
email-ext:2.102
font-awesome-api:6.4.2-1
git:5.2.0
git-client:4.5.0
github:1.37.3.1
github-api:1.318-461.v7a_c09c9fa_d63
github-branch-source:1741.va_3028eb_9fd21
gradle:2.9
hashicorp-vault-plugin:361.v44fea_4fc08d9
instance-identity:185.v303dc7c645f9
ionicons-api:56.v1b_1c8c49374e
jackson2-api:2.15.3-372.v309620682326
jakarta-activation-api:2.0.1-3
jakarta-mail-api:2.0.1-3
javadoc:243.vb_b_503b_b_45537
javax-activation-api:1.2.0-6
javax-mail-api:1.6.2-9
jaxb:2.3.9-1
jjwt-api:0.11.5-77.v646c772fddb_0
jquery3-api:3.7.1-1
jsch:0.2.8-65.v052c39de79b_2
junit:1240.vf9529b_881428
ldap:711.vb_d1a_491714dc
mailer:463.vedf8358e006b_
matrix-auth:3.2.1
matrix-project:818.v7eb_e657db_924
maven-plugin:3.23
mina-sshd-api-common:2.11.0-86.v836f585d47fa_
mina-sshd-api-core:2.11.0-86.v836f585d47fa_
okhttp-api:4.11.0-157.v6852a_a_fa_ec11
pam-auth:1.10
pipeline-build-step:516.v8ee60a_81c5b_9
pipeline-github-lib:42.v0739460cda_c4
pipeline-graph-analysis:202.va_d268e64deb_3
pipeline-groovy-lib:689.veec561a_dee13
pipeline-input-step:477.v339683a_8d55e
pipeline-milestone-step:111.v449306f708b_7
pipeline-model-api:2.2151.ve32c9d209a_3f
pipeline-model-definition:2.2151.ve32c9d209a_3f
pipeline-model-extensions:2.2151.ve32c9d209a_3f
pipeline-rest-api:2.34
pipeline-stage-step:305.ve96d0205c1c6
pipeline-stage-tags-metadata:2.2151.ve32c9d209a_3f
pipeline-stage-view:2.34
plain-credentials:143.v1b_df8b_d3b_e48
plugin-util-api:3.6.0
prism-api:1.29.0-9
resource-disposer:0.23
scm-api:683.vb_16722fb_b_80b_
script-security:1294.v99333c047434
snakeyaml-api:2.2-111.vc6598e30cc65
ssh-credentials:308.ve4497b_ccd8f4
ssh-slaves:2.916.vd17b_43357ce4
structs:325.vcb_307d2a_2782
timestamper:1.26
token-macro:384.vf35b_f26814ec
trilead-api:2.84.v72119de229b_7
variant:60.v7290fc0eb_b_cd
workflow-aggregator:596.v8c21c963d92d
workflow-api:1283.v99c10937efcb_
workflow-basic-steps:1042.ve7b_140c4a_e0c
workflow-cps:3812.vc3031a_b_a_c955
workflow-durable-task-step:1289.v4d3e7b_01546b_
workflow-job:1360.vc6700e3136f5
workflow-multibranch:756.v891d88f2cd46
workflow-scm-step:415.v434365564324
workflow-step-api:639.v6eca_cd8c04a_a_
workflow-support:865.v43e78cc44e0d
ws-cleanup:0.45

What Operating System are you using (both controller, and any agents involved in the problem)?

Ubuntu 22.04.
Running jenkins as a docker image based from jenkins/jenkins:2.430-jdk17

Reproduction steps

• Run default setup of jenkins docker with
• JAVA_OPTS: -Djenkins.install.runSetupWizard=false
• Mount /var/run/docker.sock from host to jenkins docker image
• Install default plugins.
• Install latest https://plugins.jenkins.io/docker-build-step/ plugin.
• Restart.
• Go to manage jenkins -> System -> Docker URL
• Set it to unix:///var/run/docker.sock so the nodes can communicate with docker.
• Click on test. and you get an error
  Something went wrong, cannot connect to unix:///var/run/docker.sock, cause: org.apache.hc.client5.http.HttpHostConnectException: Connect to unix://localhost:2375 [localhost/127.0.0.1] failed: Connection refused

Expected Results

After troubleshooting, I have discovered that your plugin is the root cause.
The version 5.2.1-1.1 works as expected. Anything afterwards breaks.

Actual Results

Something went wrong, cannot connect to unix:///var/run/docker.sock, cause: org.apache.hc.client5.http.HttpHostConnectException: Connect to unix://localhost:2375 [localhost/127.0.0.1] failed: Connection refused

Anything else?

The setup is plain and default. Nothing was changed to docker on the host

Are you interested in contributing a fix?

Sure. I need this fixed. Right now, I have to manually downgrade your package as I have not found a fix for the error.

[strangelookingnerd]

As this plugin here only provides the dependencies for http components "as-is" the only way to fix it would be in the http client library or the docker plugin. See jenkinsci/docker-plugin#1032

[ruskii22]

sounds like we have to wait for either of them to fix the issue. Until then, I will be forcing downgrade of this plugin. Thanks for quick response.

[MarkEWaite]

Apache http client 5.3 has now released. Is the behavior any better with the new release?

[strangelookingnerd]

@MarkEWaite I don't think so. From what I can tell it is somewhat caused / blocked by docker-java/docker-java#2183 and may be fixed by docker-java/docker-java#2262. Further there could still be something hidden in the httpclient itself but I did not yet come around to investigate any further.

[strangelookingnerd]

According to jenkinsci/docker-plugin#1032 (comment) this issue has been resolved with 5.3.1-1.0. Closing this issue 😀