After reboot, I start the ambri server using “ambari-server start” . Now the problem is that no service is running and having yellow icons.

[#1 · Accepted solution]

Your ambari agent has gone down. You can run below:

service ambari-agent restart

In general, on sandbox use below to restart Ambari:

service ambari restart 

On Ambari installed clusters you should can use below to restart Ambari

service ambari-server restart 

[#2]

@Ali Bajwa

Thanks a lot for your prompt and invaluable fix. It worked for me.

[#3]

Glad to hear!