Tag Archives: TIL

Jenkins

Terminate a stuck Jenkins job

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Sometimes (especially after an un-graceful process restart), Jenkins jobs will be stuck in a running state, and cancelling through the UI just doesn’t work.

Fortunately, jobs can be stopped via the Jenkins script console with this command (courtesy of https://stackoverflow.com/a/26306081/11125318):

Jenkins.instance.getItemByFullName("JobName")
                .getBuildByNumber(JobNumber)
                .finish(
                        hudson.model.Result.ABORTED,
                        new java.io.IOException("Aborting build")
                );

Video

VAInfo: Verify Hardware Accelerated Video Support

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On Ubuntu (and possibly other) Linux distros, run vainfo to see which Intel QuickSync profiles are supported.

For example, these profiles are supported on an Intel Haswell chip:

libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_0_39
libva info: va_openDriver() returns 0
vainfo: VA-API version: 0.39 (libva 1.7.0)
vainfo: Driver version: Intel i965 driver for Intel(R) Haswell Desktop - 1.7.0
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Simple            : VAEntrypointEncSlice
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointEncSlice
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSlice
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSlice
      VAProfileH264MultiviewHigh      : VAEntrypointVLD
      VAProfileH264MultiviewHigh      : VAEntrypointEncSlice
      VAProfileH264StereoHigh         : VAEntrypointVLD
      VAProfileH264StereoHigh         : VAEntrypointEncSlice
      VAProfileVC1Simple              : VAEntrypointVLD
      VAProfileVC1Main                : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD
      VAProfileNone                   : VAEntrypointVideoProc
      VAProfileJPEGBaseline           : VAEntrypointVLD

References:

Tools

Display HTTPS X509 Cert from Linux CLI

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Recently, while attempting a git pull, I was confronted with the following error:

Peer's certificate issuer has been marked as not trusted by the user.

The operation worked on a browser on my dev machine, and closer inspection revealed that the cert used to serve the GitLab service was valid, but for some reason the remote CentOS Linux server couldn’t pull from the remote.

I found this post on StackOverflow detailing how to retrieve the X509 cert used to secure an HTTPS connection:

echo | openssl s_client -showcerts -servername MyGitServer.org -connect MyGitServer.org:443 2>/dev/null | openssl x509 -inform pem -noout -text

This was my ticket to discover why Git on my CentOS server didn’t like the certificate: the CentOS host was resolving the wrong DNS host name, and therefore using an invalid cert for the service.

And now a Haiku:

http://i.imgur.com/eAwdKEC.png
VCS

Git: Replace Root Commit with Second Commit

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While migrating code between version control systems (in my case SourceGear Vault to Git using an open-source c# program called vault2git), it’s sometimes necessary to pre-populate the first commit in the target system.

This yields an empty commit (git commit -m "initial commit" --allow-empty) with a timestamp of today, which is chronologically out of order of the incoming change set migration.

After completing the migration, the second commit is actually the commit which I’d like to be the root.

It took me a while to figure this out, but thanks to
Greg Hewgill on Stack Overflow, I was able to replace the first commit of my branch with the second commit (and subsequently update the SHA1 hashes of all child commits) using this command:

git filter-branch --parent-filter "sed 's/-p <the__root_commit>//'" HEAD

CI/CD Tools, Jenkins

TIL: Java code in Jenkins pipelines run on the Master

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I was trying to read a file with Java.io.File in a Jenkins Groovy Scripted Pipeline on a non-master node. I kept getting an exception that the file was not found (java.io.FileNotFoundException)

Turns out that Java code written in scripted pipelines (Groovy) runs on the master node: https://issues.jenkins-ci.org/browse/JENKINS-37577. This is as-designed behavior, and accessing files in the workspace on a non-master node should use the readFile function in the Pipeline Basic Steps DSL https://jenkins.io/doc/pipeline/steps/workflow-basic-steps/#pwd-determine-current-directory

I’m thoroughly embarrassed at how many failed Jenkins jobs and alerts I’ve triggered while discovering this.