diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 417bddc68d..f40d31f5e3 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -162,7 +162,7 @@ jobs:
       - name: Print tests that are going to be run in this chunk
         run: cat tests_chunk_${{ matrix.chunk_number }}
 
-      # Run a selected chunk of tests in parallel, keep a log; on error, print out said log
+      # Run a selected chunk of tests in parallel, keep a log; on error, print out said log.
       - name: Run tests
         run: >-
           cat tests_chunk_${{ matrix.chunk_number }}
@@ -189,3 +189,7 @@ jobs:
           MC_TWITTER_ACCESS_TOKEN_SECRET: ${{ secrets.MC_TWITTER_ACCESS_TOKEN_SECRET }}
           MC_TWITTER_CONSUMER_KEY: ${{ secrets.MC_TWITTER_CONSUMER_KEY }}
           MC_TWITTER_CONSUMER_SECRET: ${{ secrets.MC_TWITTER_CONSUMER_SECRET }}
+
+      - name: List test failures and errors
+        run: echo -e 'Test failures:\n' && awk '/FAILURES/,/short/' /home/runner/runners/*/_diag/pages/*.log && echo -e '\n\nErrors:\n' && awk '/non-zero/,/status 1/' /home/runner/runners/*/_diag/pages/*.log
+        if: always()
diff --git a/apps/munin-node/Dockerfile b/apps/munin-node/Dockerfile
index 233d140918..969508a596 100644
--- a/apps/munin-node/Dockerfile
+++ b/apps/munin-node/Dockerfile
@@ -8,6 +8,7 @@ FROM gcr.io/mcback/base:latest
 RUN \
     #
     # Install plugin dependencies
+    apt-get -y update && \
     apt-get -y --no-install-recommends install \
         libdbd-pg-perl \
         libdbix-simple-perl \
diff --git a/doc/dev_test_environment.markdown b/doc/dev_test_environment.markdown
index d0631edf49..ca0f05e5e2 100644
--- a/doc/dev_test_environment.markdown
+++ b/doc/dev_test_environment.markdown
@@ -25,3 +25,7 @@ To import stories into Solr from within the test file:
     ```
 
 If you use `MediaWords::Test::Solr::setup_test_index()` helper to import test stories to Solr, it will do the importing for you.
+
+## Debugging GitHub Actions
+
+We use GitHub Actions for our build/test/deploy flow, with the configuration stored in [`.github/workflows/build.yml`](https://github.com/mediacloud/backend/blob/master/.github/workflows/build.yml). Should you need to debug this process (say, if you're attempting to add a new step and it's not working as expected), you can temporarily make use of the tmate tool (as is done in [this commit](https://github.com/mediacloud/backend/blob/2f6e85ba536a4938fb10a8b83353977a4f43dda0/.github/workflows/build.yml#L192-L196)). Said tool will expose a URL in the build log at which you can `ssh` to the GitHub Actions container. Don't forget to **remove the tmate step** when your debugging is complete. Note that you need to be a collaborator on the project for this to work.