Troubleshooting Salt clients shown as down and DNS settings

Even if the Salt client is running, actions such as package refresh or apply states can be marked as failed with the message:

Minion is down or could not be contacted.

In this case try rescheduling the action. If rescheduling succeeds, the cause of the problem can be a wrong DNS configuration.

When the Salt client is restarted, or in case the grains are refreshed, the client calculates its FQDN grains, and it is unresponsive until the grains are proceeded. When a scheduled action on Uyuni Server is going to be executed, Uyuni Server performs a to the client before the actual action to ensure the client is actually running and the action can be triggered.

By default, Uyuni Server waits for 5 seconds to get the response from command. If the response is not received within 5 seconds, then the action is set to fail with the message that the client is down or could not be contacted.

To correct this, fix the DNS resolution on the client, so the client does not get stuck for 5 seconds while solving its FQDN.

If this is not possible, try to increase the value for java.salt_presence_ping_timeout in the /etc/rhn/rhn.conf file on the Uyuni Server to a value higher than 4.

For example:

java.salt_presence_ping_timeout = 6

After that, restart spacewalk-services with:

spacewalk-services restart

Increasing this value will cause Uyuni Server to take longer to check if a minion is unreachable or unresponsive, causing the Uyuni Server to be slower or less responsive overall.