diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 09c9195..1699e65 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,47 +1,49 @@
 name: Test
 on:
   # Run CI on all pushes to the master and release/** branches, and on all new
   # pull requests, and on all pushes to pull requests (even if a pull request
   # is not against master).
   push:
     branches:
       - "master"
       - "releases/**"
   pull_request:
 env:
   DOCKER_COMPOSE_VERSION: 1.24.1
 jobs:
   test:
     strategy:
+      # Only run one job at a time as they are quite demanding
+      max-parallel: 1
       matrix:
         py2: ["", "1"]
     runs-on: ubuntu-18.04
     name: "test${{ matrix.py2 == '1' && ' PY2' || ''}}"
     steps:
       - name: Pin docker-compose
         run: |
           sudo rm /usr/local/bin/docker-compose
           curl -L https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-`uname -s`-`uname -m` > docker-compose
           chmod +x docker-compose
           sudo mv docker-compose /usr/local/bin
 
       - name: Checkout
         uses: actions/checkout@v2
 
       - name: Install and test
         env:
           COMPOSE_PARALLEL_LIMIT: 50
           COMPOSE_HTTP_TIMEOUT: 450
           SENTRY_PYTHON2: ${{ matrix.py2 == '1' || '' }}
         run: |
           ./install.sh
           ./test.sh
           printf "Testing in-place upgrade"
           ./install.sh --minimize-downtime
           ./test.sh
 
       - name: Inspect failure
         if: failure()
         run: |
           docker-compose ps
           docker-compose logs