diff --git a/.github/workflows/k8s_e2e.yml b/.github/workflows/k8s_e2e.yml
index 70710521b4694..61cdd84090754 100644
--- a/.github/workflows/k8s_e2e.yml
+++ b/.github/workflows/k8s_e2e.yml
@@ -101,6 +101,7 @@ jobs:
       - run: sudo -E bash scripts/ci-free-disk-space.sh
       - run: sudo -E bash scripts/environment/bootstrap-ubuntu-24.04.sh
       - run: bash scripts/environment/prepare.sh
+      - run: ~/.cargo/bin/rustup target add x86_64-unknown-linux-gnu
       - run: echo "::add-matcher::.github/matchers/rust.json"
       - run: VECTOR_VERSION="$(cargo vdev version)" make package-deb-x86_64-unknown-linux-gnu
 
diff --git a/.github/workflows/msrv.yml b/.github/workflows/msrv.yml
index bad4f25cc7cab..18a70126da711 100644
--- a/.github/workflows/msrv.yml
+++ b/.github/workflows/msrv.yml
@@ -18,5 +18,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - run: sudo -E bash scripts/environment/bootstrap-ubuntu-24.04.sh
+      - run: |
+          # We usually run `scripts/environment/prepare.sh` but in this case we only need the toolchain.
+          rustup show active-toolchain || rustup toolchain install
       - run: cargo install cargo-msrv --version 0.15.1
       - run: cargo msrv verify
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f12aedad99ddd..c30215f33bf49 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -126,6 +126,7 @@ jobs:
         if: needs.changes.outputs.source == 'true' || needs.changes.outputs.dependencies == 'true'
         run: |
           cd lib/vector-vrl/web-playground/
+          ~/.cargo/bin/rustup target add wasm32-unknown-unknown
           wasm-pack build --target web --out-dir public/pkg
 
   # This is a required status check, so it always needs to run if prior jobs failed, in order to mark the status correctly.
diff --git a/scripts/environment/prepare.sh b/scripts/environment/prepare.sh
index ca8aff9c0d4ec..f7b0f2508516b 100755
--- a/scripts/environment/prepare.sh
+++ b/scripts/environment/prepare.sh
@@ -3,8 +3,8 @@ set -e -o verbose
 
 git config --global --add safe.directory /git/vectordotdev/vector
 
-rustup show # causes installation of version from rust-toolchain.toml
-rustup default "$(rustup show active-toolchain | awk '{print $1;}')"
+rustup show active-toolchain || rustup toolchain install
+rustup show
 if [[ "$(cargo-deb --version)" != "2.0.2" ]] ; then
   rustup run stable cargo install cargo-deb --version 2.0.0 --force --locked
 fi
diff --git a/src/sources/host_metrics/tcp.rs b/src/sources/host_metrics/tcp.rs
index 316d40d087930..c45eb164c11ba 100644
--- a/src/sources/host_metrics/tcp.rs
+++ b/src/sources/host_metrics/tcp.rs
@@ -273,6 +273,8 @@ mod tests {
         assert_eq!(*tcp_stats.conn_states.get("syn_recv").unwrap(), 1.0);
     }
 
+    #[ignore]
+    /// These tests are flakey and need reworking.
     /// This is a workaround for running these tests serially.
     /// The `generates_tcp_metrics` test internally calls `fetch_nl_inet_hdrs` and reads
     /// from the same socket as the `fetches_nl_net_hdrs` test.