Parallelisation of Azure Pipelines - azure

Question

I have a pipeline (in YAML) which upgrades an infrastructure(I have 2 stages each containing a series of jobs)
I now want to upgrade multiple infrastructures simultaneously i.e. pass a list of identifiers which represents deployments to the pipeline and then let it upgrade each.
What is the best practice here for organising the pipeline? It feels like I need to generate a set of parallel jobs using a loop?
As I understand it any job failure will result in a total failure which could leave us in a very confused state.

Answer 1

If you purchased parallel jobs for your organization. You can use Template to generate multiple jobs according the identities parameter using expression ${{each id in parameters.identities}}.
So you can move the job which upgrades the infrastructures into a template and define your yaml pipeline as below. See below example:
Template file: upgrade-infrastructure.yml
parameters:
id: 1
jobs:
- job: upgradeinfra${{parameters.id}}
steps:
- powershell: echo "upgrade-infra-${{parameters.id}}"
azure-pipelines.yml:
#define the identities as a object to hold a array object of ids
parameters:
- name: identities
type: object
default:
ids:
- 1
- 2
trigger: none
stages:
- stage: Upgrage
pool:
vmImage: windows-latest
jobs:
- job: A
steps:
- powershell: echo "job A"
#loop through the ids array object and the each id to the template paramter to generate multiple jobs for each id.
#indentation is very important, bad indentation may cause pipeline compile error.
- ${{ each id in parameters.identities.ids }}:
- template: upgrade-infrastructure.yml
parameters:
id: ${{id}}
After you set up your yaml pipeline as above, you can enter the identities in the parameter when executing the pipeline:
Then you will see the multiple jobs are generated and run in parallel:

Answer 2

To make your deployments run in parallel, all you need to do is to set the dependencies. (The dependency on the previous step is automatically set). Here is an example of a stage that only depends on the build before all stage will run in parallel:
stage:
-stages : DeployTo${{ parameters.environment }}
dependsOn: ["Build"] //The stage that build the code is called "Build"
The Result looks like this:
Without the dependsOn property your pipeline stages will run sequentially and looks like this:
stages:
-stage : DeployTo${{ parameters.environment }}