I have installed agent on VM and configured a CI build pipeline. The pipeline is triggered and works perfectly fine.
Now I want to use same build pipeline, same agent, but different VM. Is this possible?
How will the execution happen for builds and on which VM will the source be copied?
Thank you.
Like the others I'm also not sure what you're trying to do and also think that the same agent across multiple machines is not possible.
But if you have to alternate or choose easily between VMs, you could set up for each of your VMs (used for this special scenario) an individual agent queue with one agent in that pool. That way you can choose the agent pool at queue time via the agent queue dropdown field. But that would only work if you're triggering manually, not in a typical CI scenario. In that case you would have to edit the definition to enforce any particular VM each time you want to swap VMs.
NO. These private agents are supposed to have a unique name and are assigned to an Agent Pool/Queue. They are polling up to VSTS/Azure Devops server if they have a job to do. Then they execute it. If you clone a machine with the same private build agent, then theoretically the agent that picks it up will execute the job, but that is theoretic. I really don't know how the Agent Queues will handle this.
It depends on what you want to do.
If you want to spread the workload, like 2 build servers and have builds go to whichever build server isn't busy, then you would create 1 Agent Pool/Queue. Create a Private Agent on one server and register it to that Pool, then on the second server un-register the agent and then re-register the agent add it to the SAME pool.
If you want to do work on 2 servers at the exact same time, like a deployment to 2 servers at the same time, then you would create a 'Deployment Group' and add both servers to that. You would unregister both agents from the Agent Pool/Queue. From your 'Deployment Group' copy the PowerShell script snippet and run it on each machine. This way you can use this in your Release Pipeline and deployments in parallel, which take less time to do deployments.
You could set up a variable in the pipeline so you can specify the name of the VM at build-time.
Also, once you have one or more agents, you would add them to an app pool. When builds are run, it will choose one agent from the pool and use that.
Related
Is there any description about the algorithm by which Azure DevOps selects the next free agent?
Our scenario is that we will run multiple agents on a single vm and we will have multiple such VMs in our VMSS that we will manually scale in and out (first based on cron schedules).
In order to best utilize the available VMs we would like to make sure that the jobs are evenly distributed on all VMs.
Meaning first run only one job (on the respective agent) per VM. If there are more jobs than VMs than share the jobs so that 2 jobs per VM are processed. Then continue like that until all agents are busy.
What I want to avoid is that the first VM is loaded with jobs until its full and then the next VM.
So I am asking myself how I can influence the selection mechanism to find the next free agent.
Thank you
PS. Such a “load balancing” is already inbuilt in Jenkins.
I am using Windows Self hosted agent for my Azure DevOps pipelines. Currently the pipelines are executed sequentially. If more than one pipelines triggered from different ADO projects, then it has to wait in queue to get the agent. In order to execute the pipeline in parallel, I came to know from some tutorials if we increase the paid parallel jobs for self hosted agent under billing section of Organization setting. Is my understanding correct? If so what are the precautionary steps I need to take. Do we have any control of when the pipelines to be executed in parallel?
Thanks.
In order to run self-hosted parallel jobs, you need to purchase parallel jobs and register several self-hosted agents.
For parallel jobs, you can register any number of self-hosted agents in your organization. If you want to run 3 jobs in parallel, then you must register at least 3 self-hosted agents in one agent pool. DevOps charges based on the number of jobs you want to run at a time, not the number of agents registered. There are no time limits on self-hosted jobs. For private projects, you can have one job and one additional job for each active Visual Studio Enterprise subscriber who is a member of your organization.
About how to purchase parallel jobs, please refer to Buy parallel jobs.
For how to control the use of parallel jobs, please refer to the following:
For classic pipeline, you can specify when to run the job through dependencies and Run this job in Additional options in the agent job. Then the pipeline will run in sequence according to your settings.
For YAML pipeline, you can specify the conditions under which the job should run with "dependsOn" and "condition".
For example:
For more info about conditions, please refer to Specify conditions
If you don't specify a specific order, the jobs will run in parallel based on the parallel jobs you purchased.
I don't know if my experience can help. I'll try. I started a new job and we use self-hosted TFS / Azure DevOps. I am changing our build process to create 3 product SKUs (it uses conditional compilation). Let's call them Good, Better & Best.
I edited the Build definition. First I switched to the Variables tab. I created a Process variable named SKUs and set it to Good,Better,Best. The commas are important.
Next I switched to the Tasks tab. I located the Agent Phase. Mine was called Phase 1. Select it. On the right, under Parallelism, I selected Multi-configuration. In the Multipliers text field I entered SKUs. I set Maximum number of agents to 3.
What I don't yet know is the TFS back-end administration and options that the company purchased beforehand.
We have a cloud full of self-hosted Azure Agents running on custom AMIs. In some cases, I have some cleanup operations which I'd really like to do either before or after a job runs on the machine, but I don't want the developer waiting for the job to wait either at the beginning or the end of the job (which holds up other stages).
What I'd really like is to have the Azure Agent itself say "after this job finishes, I will run a set of custom scripts that will prepare for the next job, and I won't accept more work until that set of scripts is done".
In a pinch, maybe just a "cooldown" setting would work -- wait 30 seconds before accepting another job. (Then at least a job could trigger some background work before finishing.)
Has anyone had experience with this, or knows of a workable solution?
I suggest three solutions
Create another pipeline to run the clean up tasks on agents - you can also add demand for specific agents (See here https://learn.microsoft.com/en-us/azure/devops/pipelines/process/demands?view=azure-devops&tabs=yaml) by Agent.Name -equals [Your Agent Name]. You can set frequency to minutes, hours, as you like using cron pattern. As while this pipeline will be running and taking up the agent, the agent being cleaned will not be available for other jobs. Do note that you can trigger this pipeline from another pipeline, but if both are using the same agents - they can just get deadlocked.
Create a template containing scripts tasks having all clean up logic and use it at the end of every job (which you have discounted).
Rather than using static VM's for agent hosting, use Azure scaleset for Self hosted agents - everytime agents are scaled down they are gone and when scaled up they start fresh. This saves a lot of money in terms of sitting agents not doing anything when no one is working. We use this option and went away from static agents. We have also used packer to create the VM image/vhd overnight to update it with patches, softwares required, and docker images cached.
ref: https://learn.microsoft.com/en-us/azure/devops/pipelines/agents/scale-set-agents?view=azure-devops
For those discovering this question, there's a much better way: run your self-hosted agent with the --once flag, documented here.
You'll need to wrap it in your own bash script, but something like this works:
while :
do
echo "Performing pre-job setup..."
echo "Waiting for job..."
./run.sh --once
echo "Cleaning up..."
sleep 2
done
Another option would be to use a ScaleSet VM setup which preps a new agent for each run and discards the VM when the run is done. It can prepare new VMs in the background while the job is running.
And I suspect you could implement your own IMaintenanceProvirer..
https://github.com/microsoft/azure-pipelines-agent/blob/master/src/Agent.Worker/Maintenance/MaintenanceJobExtension.cs#L53
I have multiple local on-prem agents that can run a particular deployment group job (for the purpose of load balancing). I want only the first available one to run the job and not all of them. Which setting of the Deployment Group Job I can use to do that? My only options seems to be "Multiple" and "Single at a time" both of which run the jobs on all servers matching the Required Tags.
I want only the first available one to run the job and not all of them. Which setting of the Deployment Group Job I can use to do that?
There is an option for the Release pipeline with Deployment Group job Required tags：
Then we just need to add the tag to the machine, which we want to deploy:
Now, the release pipeline will run a Deployment Group Job in one of the matching servers.
Update:
I do have the required tag, but on two agent servers. I want the Job
to pick only one of the two matching servers and run the job on it
instead of running it on both.
As workaround, you could create a private agent pool and add two or more agents in it. Those agents are deployed on different machines. With this way, the pipeline will executed on one of the agent.
https://learn.microsoft.com/en-us/azure/devops/pipelines/agents/v2-windows?view=azure-devops&viewFallbackFrom=vsts
After reading the very short official documents about the azure pipeline agent, I am getting very confused.
What exactly is an azure pipeline agent?
What is an agent job?
What's the relationship between agent and VM?
What's the relationship between agent job and VM? For each agent， one VM will be temporally assigned to it and will be back to the pool after the agent job finished?
If 2 different agent jobs run by 2 agents need the same running environment and the VM is agent job dependent. How should I retain the first agent job's running environment after it's finished running? Recreated again?
If each agent needs a VM, why create this concept? why not just directly use the VM or container?
Pipeline agent is machine where your build is performed. An agent is installable software that runs one job at a time.
Agent job is a set of steps which is recognized as execution boundary. Each job runs on an agent. All of the steps run together on the same agent.
From that perspective you can distinguish two kind of jobs - the onces installed on VM and onces instaled on container.
Agent job runs on agent which can be installed on VM. VM's are not assigned. Agents are assigned. There is agent pool, not VM pool.
I don't understand this one. Agents after finishing their job are going back to pool.
You may have more agents on on VM for instance one agents is installed on VM and few others as containers.
Please take a look here. You will find explanation for these concepts.