Every Linux step now runs under ci/guard-step.py. The first step that fails, is cancelled or times out marks the pipeline; running steps get SIGTERM (so traps release flock and Buildah state) then SIGKILL, steps that have not started exit at once, and any process a step leaves behind is killed. A pipeline deadline is the last resort. build-linux-agent.sh now prints the lookup error, store configuration and the restore images present when the prepared restore image cannot be found.