In both it takes cron expression as input, so what's the actual difference between these two.
Poll SCM periodically polls the SCM to check whether changes were made (i.e. new commits) and builds the project if new commits where pushed since the last build, whereas build periodically builds the project periodically even if nothing has changed.
Related
I'm setting up a new Jenkins job using multibranch pipeline and I have noticed that when a branch is deleted, it only has a strikethrough and isn't actually removed on Jenkins. This is solved by re-running branch indexing. However, I cannot really use this as it will also cause every other branch to rebuild (a consequence of how the repository is updated). Is there some custom code or pipeline/script I can run to re-index without building?
I've already looked at various UI methods such as suppressing SCM triggers, but this also negates push events from Github which is something we want to use.
The deleted/merged branch build will disappear after a period of time (<24 hours). It is not removed immediately to show the recently deleted/merged branches and give a chance to review the prior build statuses. It is relatively harmless since the jobs for these branches are deactivated (read-only).
Note that the removal is based on the branch indexing job running at regular interval, so if you have this disabled, it probably won't do it (not sure the SCM webhook calls are enough).
Is there a possible to prevent the full jenkins job from running, that is periodically scheduled; if there is no SCM changes since the last build.
For example,
There is a daily night build, to create a build. The completion of this job triggers(upstream project) the automation testing job for that build.
I would like to be able to have two things
Stop the 1st build job, if there is no SCM change since the last job
2nd upstream automation test job runs only if it has not run for 1 week. (after it has been triggered by the 1st Job)
Thanks in advance
The first part is simple, instead of "Build periodically" set to "Poll SCM" with the same schedule. It's exactly what it does: periodically checking for changes and only running the job if there were some.
The second part (triggering another job with a time constraint) is more complicated. One option is "Throttle builds" (to 1 per week) in addition to your usual build triggering scheme. Another one is "Trigger builds remotely (e.g., from scripts)" option and checking whether required conditions are met in some sort of script or service.
For the first
Did you try the poll the SCM every night? If no changes, the Jenkins job wont start.
0 23 * * *
Will run every night at 11 p.m
for the second
use the following plugin : https://wiki.jenkins.io/display/JENKINS/Run+Condition+Plugin
I have just setup a basic multibranch pipeline build job and have a feature branch with a jenkinsfile present which I am experimenting with.
I have the job configured to poll the scm every 5 mins and trigger a build if necessary.
I am finding however at times when I manually start a build for my branch after I have pushed up a tweak on my Jenkinsfile for example (as I don't want to wait for the next scm poll interval), the branch re-indexing activity can still trigger another build to be performed.
See the image below for what I mean, so here build 7 is one I kicked off manually on jenkins, so it picked up my commit, but then the branch indexing kicked off build 8 but there were no new changes for the branch.
Is there a way to prevent this from happening? Other than me being patient and waiting 5 mins of course!
Thanks
I experienced this also. I tried playing with the polling settings in the Multibranch pipeline to see if this could fix it but that only led to no builds being spawned at all in response to SCM changes.
So this behaviour to which you refer was the best of a bad lot.
At time of writing, I think this behaviour is a bug with no current resolution.
Can't remember if I raised a ticket or not as I am in Azure DevOps world now.
I've set up a number of Multibranch Pipeline jobs in Jenkins (running 2.46.2 LTS, Branch API 2.0.8, GitHub Branch Source 2.0.5, and Pipeline Multibranch 2.14) and have just noted that branch indexing -- and thus any cleanup of old branches -- does not appear to be triggered by the webhook calls from GitHub. It only appears to be triggered if someone manually clicks the "Scan Repository Now" link, or if the job configuration in Jenkins is re-saved. I'm using the timestamp shown in the "Scan Repository Log" page as an indication of when the branch indexing occurs.
It seems that new branches or changes to existing ones are being detected correctly and built, so the webhooks from source control (GitHub) are working, but was surprised that this wasn't also triggering the branch indexing and thus the old branch cleanup. I just can't tell from the documentation whether this is correct and expected behavior or if something is incorrect in my setup.
I note that the help text for the "Periodically if not otherwise run" setting says:
Some kinds of folders are reindexed automatically and immediately upon receipt of an external event. For example, a multi-branch project will recheck its SCM repository for new or removed or modified branches when it receives an SCM change notification. (Push notification may be configured as per the SCM plugin used for each respective branch source.) Such notifications can occasionally be unreliable, however, or Jenkins might not even be running to receive them. In some cases no immediate notification is even possible, for example because Jenkins is behind a firewall and can only poll an external system.
This trigger allows for a periodic fallback, but when necessary. If no indexing has been performed in the specified interval, then an indexing will be scheduled. For example, in the case of a multi-branch project, if the source control system is not configured for push notification, set a short interval (most people will pick between 15 minutes and 1 hour). If the source control system is configured for push notification, set an interval that corresponds to the maximum acceptable delay in the event of a lost push notification as the last commit of the day. (Subsequent commits should trigger indexing anyway and result in the commit being picked up, so most people will pick between 4 hours and 1 day.)
This certainly implies that indexing of a Multibranch Pipeline job should be re-triggered by branch events (e.g., pushes from GitHub via webhook), but the timestamp on my indexing log seems to belie that.
So, is what I'm observing the intended behavior? If so, and I want a regular cleanup of old branches, do I need to select the "Periodically if not otherwise run" checkbox under "Scan repository triggers"? Or is there something wrong with my setup, which is preventing it from working as intended?
According to the official documentation:
By default, Jenkins will not automatically re-index the repository for branch additions or deletions (unless using an Organization Folder), so it is often useful to configure a Multibranch Pipeline to periodically re-index in the configuration.
I depend on "Periodically if not otherwise run" for 1) cleanup of branches and 2) creation of container jobs for brand new repos (i use "Bitbucket Team/Project", the bitbucket version of "Github Organization", which basically creates a multibranch pipeline for every repo in your organization). I have "Periodically if not otherwise run" set to run once a day for each project.
It does seem like these things could work via webhook, but they do not in my experience.
I have a job that takes a while to complete and is quite resource heavy. I only ever want to run one instance of the job at a time, and only if there are new SCM changes.
I set it up with an SCM trigger and left off the checkbox "Execute concurrent builds if necessary".
The problem I have is that it queues up the next build on the first SCM change it detects.
What I want is that whenever the SCM trigger sees a change, that it replaces the job it queued up with a new job, with the newer SCM revision. I don't want it running a new instance with the next change, and I don't want a ton of jobs queued up.
Basically, I want the job to run in a loop, and only pause if there are no SCM changes.
How do I do that?
You might be looking for Quiet period option which is under Advanced Project Options section.
You can set the value (in seconds) for Quiet period as per your requirement. This will help you reduce the frequency of builds.