Use the ephemeral mount for builds too

Author: keithduncan

packer/linux/conf/bin/bk-install-elastic-stack.sh

@@ -141,6 +141,12 @@ if [[ "${BUILDKITE_AGENT_ENABLE_GIT_MIRRORS_EXPERIMENT}" == "true" ]] ; then
   fi
 fi
 
+BUILDKITE_AGENT_BUILD_PATH="/var/lib/buildkite-agent/builds"
+if [ "${BUILDKITE_ENABLE_INSTANCE_STORAGE:-false}" == "true" ]
+then
+	BUILDKITE_AGENT_BUILD_PATH="/mnt/ephemeral/builds"
+fi
+
 BUILDKITE_AGENT_TOKEN="$(aws ssm get-parameter --name "${BUILDKITE_AGENT_TOKEN_PATH}" --with-decryption --query Parameter.Value --output text)"
 
 cat << EOF > /etc/buildkite-agent/buildkite-agent.cfg
@@ -150,7 +156,7 @@ tags=$(IFS=, ; echo "${agent_metadata[*]}")
 tags-from-ec2-meta-data=true
 timestamp-lines=${BUILDKITE_AGENT_TIMESTAMP_LINES}
 hooks-path=/etc/buildkite-agent/hooks
-build-path=/var/lib/buildkite-agent/builds
+build-path=${BUILDKITE_AGENT_BUILD_PATH}
 plugins-path=/var/lib/buildkite-agent/plugins
 git-mirrors-path="${BUILDKITE_AGENT_GIT_MIRRORS_PATH}"
 experiment="${BUILDKITE_AGENT_EXPERIMENTS}"