--- layout: "docs" page_title: "Agent Uptime Recipe" sidebar_current: "docs-recipes" description: |- On occasion users have asked for the ability to identify the uptime of a Serf agent. While Serf does not expose this directly in the RPC layer, it is quite easy to utilize tags to accomplish this. --- # Recipe: Agent Uptime On occasion users have asked for the ability to identify the uptime of a Serf agent. While Serf does not expose this directly in the RPC layer, it is quite easy to utilize tags to accomplish this. The solution is simple. While starting a Serf agent, add a tag to indicate the time at which it was started: ``` serf agent -tag start_time=`date +%s` ``` While the agent is running, you can retrieve its uptime in seconds by getting the current UNIX timestamp and doing simple subtraction.