Define variable group

.azure-pipelines/templates/jobs/deployment-jobs.yml

@@ -2,6 +2,8 @@ jobs:
   - job: publish_snap
     pool:
       vmImage: ubuntu-18.04
+    variables:
+      - group: certbot-common
     steps:
       - bash: |
           sudo apt-get update

.azure-pipelines/templates/jobs/extended-tests-jobs.yml

@@ -1,9 +1,13 @@
 jobs:
   - job: x_test
     variables:
-      IMAGE_NAME: ubuntu-18.04
+      - name: IMAGE_NAME
+        value: ubuntu-18.04
+      ${{ if contains(variables['TOXENV'], 'test-farm') }}:
+      - group: certbot-common
       ${{ if contains(variables['TOXENV'], 'integration') }}:
-        PYTEST_ADDOPTS: --numprocesses 4
+      - name: PYTEST_ADDOPTS
+        value: --numprocesses 4
     strategy:
       matrix:
         linux-py36:

.azure-pipelines/templates/stages/notify-failure-stage.yml

@@ -2,6 +2,8 @@ stages:
   - stage: On_Failure
     jobs:
       - job: notify_mattermost
+        variables:
+          - group: certbot-common
         pool:
           vmImage: ubuntu-latest
         steps: