diff --git a/.github/buildomat/jobs/build-and-test-linux.sh b/.github/buildomat/jobs/build-and-test-linux.sh
new file mode 100644
index 00000000000..fb65dc7ba08
--- /dev/null
+++ b/.github/buildomat/jobs/build-and-test-linux.sh
@@ -0,0 +1,73 @@
+#!/bin/bash
+#:
+#: name = "build-and-test (ubuntu-20.04)"
+#: variety = "basic"
+#: target = "ubuntu-20.04"
+#: rust_toolchain = "nightly-2022-04-27"
+#: output_rules = [
+#:	"/var/tmp/omicron_tmp/*",
+#:	"!/var/tmp/omicron_tmp/crdb-base*",
+#:	"!/var/tmp/omicron_tmp/rustc*",
+#: ]
+#:
+
+set -o errexit
+set -o pipefail
+set -o xtrace
+
+cargo --version
+rustc --version
+
+#
+# Set up a custom temporary directory within whatever one we were given so that
+# we can check later whether we left detritus around.
+#
+TEST_TMPDIR='/var/tmp/omicron_tmp'
+echo "tests will store output in $TEST_TMPDIR" >&2
+mkdir "$TEST_TMPDIR"
+
+#
+# Put "./cockroachdb/bin" and "./clickhouse" on the PATH for the test
+# suite.
+#
+export PATH="$PATH:$PWD/out/cockroachdb/bin:$PWD/out/clickhouse"
+
+banner prerequisites
+ptime -m bash ./tools/install_builder_prerequisites.sh -y
+
+#
+# We build with:
+#
+# - RUSTFLAGS="-D warnings" RUSTDOCFLAGS="-D warnings": disallow warnings
+#   in CI builds.  This can result in breakage when the toolchain is
+#   updated, but that should only happen with a change to the repo, which
+#   gives us an opportunity to find and fix any newly-introduced warnings.
+#
+# - `--locked`: do not update Cargo.lock when building.  Checking in
+#   Cargo.lock ensures that everyone is using the same dependencies and
+#   also gives us a record of which dependencies were used for each CI
+#   run.  Building with `--locked` ensures that the checked-in Cargo.lock
+#   is up to date.
+#
+banner build
+export RUSTFLAGS="-D warnings"
+export RUSTDOCFLAGS="-D warnings"
+export TMPDIR=$TEST_TMPDIR
+ptime -m cargo +'nightly-2022-04-27' build --locked --all-targets --verbose
+
+#
+# NOTE: We're using using the same RUSTFLAGS and RUSTDOCFLAGS as above to avoid
+# having to rebuild here.
+#
+banner test
+ptime -m cargo +'nightly-2022-04-27' test --workspace --locked --verbose \
+    --no-fail-fast
+
+#
+# Make sure that we have left nothing around in $TEST_TMPDIR.  The easiest way
+# to check is to try to remove it with `rmdir`.
+#
+unset TMPDIR
+echo "files in $TEST_TMPDIR (none expected on success):" >&2
+find "$TEST_TMPDIR" -ls
+rmdir "$TEST_TMPDIR"
diff --git a/.github/buildomat/jobs/build-and-test.sh b/.github/buildomat/jobs/build-and-test.sh
index 50dc04a1f41..eb5c241b389 100644
--- a/.github/buildomat/jobs/build-and-test.sh
+++ b/.github/buildomat/jobs/build-and-test.sh
@@ -4,7 +4,11 @@
 #: variety = "basic"
 #: target = "helios-latest"
 #: rust_toolchain = "nightly-2022-04-27"
-#: output_rules = []
+#: output_rules = [
+#:	"/var/tmp/omicron_tmp/*",
+#:	"!/var/tmp/omicron_tmp/crdb-base*",
+#:	"!/var/tmp/omicron_tmp/rustc*",
+#: ]
 #:
 
 set -o errexit
@@ -18,9 +22,9 @@ rustc --version
 # Set up a custom temporary directory within whatever one we were given so that
 # we can check later whether we left detritus around.
 #
-TEST_TMPDIR="${TMPDIR:-/var/tmp}/omicron_tmp"
-echo "tests will store output in $TEST_TMPDIR"
-mkdir $TEST_TMPDIR
+TEST_TMPDIR='/var/tmp/omicron_tmp'
+echo "tests will store output in $TEST_TMPDIR" >&2
+mkdir "$TEST_TMPDIR"
 
 #
 # Put "./cockroachdb/bin" and "./clickhouse" on the PATH for the test
@@ -56,13 +60,14 @@ ptime -m cargo +'nightly-2022-04-27' build --locked --all-targets --verbose
 # having to rebuild here.
 #
 banner test
-ptime -m cargo +'nightly-2022-04-27' test --workspace --locked --verbose
+ptime -m cargo +'nightly-2022-04-27' test --workspace --locked --verbose \
+    --no-fail-fast
 
 #
 # Make sure that we have left nothing around in $TEST_TMPDIR.  The easiest way
 # to check is to try to remove it with `rmdir`.
 #
 unset TMPDIR
-echo "files in $TEST_TMPDIR (none expected on success):"
-find $TEST_TMPDIR -ls
-rmdir $TEST_TMPDIR
+echo "files in $TEST_TMPDIR (none expected on success):" >&2
+find "$TEST_TMPDIR" -ls
+rmdir "$TEST_TMPDIR"
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 9d63cd8976f..7c71125c96e 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -78,88 +78,3 @@ jobs:
       run: ./tools/install_builder_prerequisites.sh -y
     - name: Test build documentation
       run: RUSTDOCFLAGS="-Dwarnings" cargo doc
-
-  build-and-test:
-    env:
-      OMICRON_TMP: /tmp/omicron_tmp
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ ubuntu-18.04 ]
-    steps:
-    # actions/checkout@v2
-    - uses: actions/checkout@28c7f3d2b5162b5ddd3dfd9a45aa55eaf396478b
-    - uses: Swatinem/rust-cache@v1
-      if: ${{ github.ref != 'refs/heads/main' }}
-    - name: Report cargo version
-      run: cargo --version
-    - name: Remove unnecessary software
-      run: |
-        echo "Disk space:"
-        df -h
-
-        if [ -d "/usr/share/dotnet" ]; then
-          echo "Removing dotnet"
-          sudo rm -rf /usr/share/dotnet
-        fi
-        if [ -d "/usr/local/lib/android" ]; then
-          echo "Removing android"
-          sudo rm -rf /usr/local/lib/android
-        fi
-        if [ -d "/usr/local/.ghcup" ]; then
-          echo "Removing haskell"
-          sudo rm -rf /usr/local/.ghcup
-        fi
-        if [ -d "/opt/hostedtoolcache/CodeQL" ]; then
-          echo "Removing CodeQL"
-          sudo rm -rf /opt/hostedtoolcache/CodeQL
-        fi
-        if [ -d "/usr/share/swift" ]; then
-          echo "Removing swift"
-          sudo rm -rf /usr/share/swift
-        fi
-
-        echo "Disk space:"
-        df -h
-    - name: Update PATH
-      run: echo "$PWD/out/cockroachdb/bin:$PWD/out/clickhouse" >> "$GITHUB_PATH"
-    - name: Install Pre-Requisites
-      run: ./tools/install_builder_prerequisites.sh -y
-    - name: Create temporary directory for test outputs
-      run: mkdir -p $OMICRON_TMP
-    - name: Build
-      # We build with:
-      # - RUSTFLAGS="-D warnings" RUSTDOCFLAGS="-D warnings": disallow warnings
-      #   in CI builds.  This can result in breakage when the toolchain is
-      #   updated, but that should only happen with a change to the repo, which
-      #   gives us an opportunity to find and fix any newly-introduced warnings.
-      # - `--locked`: do not update Cargo.lock when building.  Checking in
-      #   Cargo.lock ensures that everyone is using the same dependencies and
-      #   also gives us a record of which dependencies were used for each CI
-      #   run.  Building with `--locked` ensures that the checked-in Cargo.lock
-      #   is up to date.
-      # - TMPDIR=$OMICRON_TMP: we specify a specific temporary directory so that
-      #   failed test outputs will be in a known place that we can grab at the
-      #   end without also grabbing random other temporary files.
-      run: TMPDIR=$OMICRON_TMP RUSTFLAGS="-D warnings" RUSTDOCFLAGS="-D warnings" cargo build --locked --all-targets --verbose
-    - name: Run tests
-      # Use the same RUSTFLAGS and RUSTDOCFLAGS as above to avoid having to
-      # rebuild here.
-      run: TMPDIR=$OMICRON_TMP RUSTFLAGS="-D warnings" RUSTDOCFLAGS="-D warnings" cargo test --no-fail-fast --workspace --locked --verbose
-    - name: Archive results left by tests
-      # actions/upload-artifact@v2.3.1
-      uses: actions/upload-artifact@82c141cc518b40d92cc801eee768e7aafc9c2fa2
-      with:
-        name: failed_test_outputs_${{ runner.os }}
-        retention-days: 7
-        path: |
-          ${{ env.OMICRON_TMP }}
-          !${{ env.OMICRON_TMP }}/crdb-base
-          !${{ env.OMICRON_TMP }}/rustc*
-    # Fail the build if successful tests leave detritus in $TMPDIR.  The easiest
-    # way to check if the directory is empty is to try to remove it with
-    # `rmdir`.
-    - name: Remove temporary directory on success (if this fails, tests leaked files in TMPDIR)
-      if: ${{ success() }}
-      run: rmdir $OMICRON_TMP