diff --git a/README.md b/README.md
index f85fd86..5d51408 100644
--- a/README.md
+++ b/README.md
@@ -144,6 +144,10 @@ immudb_database: <immudb database name to be used>
 immudb_address: <url in format `host:port` of immudb instance, default port is 3322>
 immudb_public_key_file: <path of the public key to use>
 
+# minutes a build task may go without a ping from its build node before it
+# expires and becomes available for a build node to pick up again (default: 20)
+build_task_expiration_minutes: <number of minutes, e.g. 20>
+
 ```
 Of course, you can override the service's default users, passwords and rabbitmq params.
 ```yaml
diff --git a/roles/dev_deploy/templates/vars.env.j2 b/roles/dev_deploy/templates/vars.env.j2
index 250b7e8..051067a 100644
--- a/roles/dev_deploy/templates/vars.env.j2
+++ b/roles/dev_deploy/templates/vars.env.j2
@@ -55,3 +55,4 @@ IMMUDB_PASSWORD="{{ immudb_password }}"
 IMMUDB_DATABASE="{{ immudb_database }}"
 IMMUDB_ADDRESS="{{ immudb_address }}"
 IMMUDB_PUBLIC_KEY_FILE="{{ immudb_public_key_file }}"
+BUILD_TASK_EXPIRATION_MINUTES="{{ build_task_expiration_minutes | default(20) }}"