buildkite: clean up docker containers from previous jobs

.buildkite/hooks/libhook

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# Copyright 2025 The gVisor Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+clear_docker_containers() {
+  # Kill any running containers (clear state), except for "bootstrap".
+  for id_and_name in $(docker ps --format='{{.ID}}/{{.Names}}'); do
+    if [[ "$(echo "$id_and_name" | cut -d'/' -f2-)" == 'bootstrap' ]]; then
+      continue
+    fi
+    timeout --kill-after=10s --preserve-status 30s \
+      docker container kill "$(echo "$id_and_name" | cut -d'/' -f1)"
+  done
+}

.buildkite/hooks/post-command

@@ -1,5 +1,7 @@
 set -x
 
+source .buildkite/hooks/libhook
+
 # Clear any downloaded credentials.
 rm -f repo.key
 
@@ -70,14 +72,7 @@ if test "${BUILDKITE_COMMAND_EXIT_STATUS}" -ne "0"; then
   sudo rm -rf "${HOME}/go"
 fi
 
-# Kill any running containers (clear state), except for "bootstrap".
-for id_and_name in $(docker ps --format='{{.ID}}/{{.Names}}'); do
-  if [[ "$(echo "$id_and_name" | cut -d'/' -f2-)" == 'bootstrap' ]]; then
-    continue
-  fi
-  timeout --kill-after=10s --preserve-status 8s \
-      docker container kill "$(echo "$id_and_name" | cut -d'/' -f1)"
-done
+clear_docker_containers
 
 set -euo pipefail
 

.buildkite/hooks/pre-command

@@ -1,5 +1,9 @@
 set -euo pipefail
 
+source .buildkite/hooks/libhook
+
+clear_docker_containers
+
 # Use a per-day bazel remote cache. As the cache object's TTL expires, they are
 # deleted on an ongoing basis. Such partial deletion can break the cache state.
 # Using per day cache will ensure that builds triggered on a certain day have