I encountered a server not running yetexception error while working today. The symptom is that it is normal to enter HBase shell, but this error will be thrown when executing any instruction.

There is no error message when checking the log. At first I thought there was HBase process not up, but the JPS command showed that all started.

It’s a little tricky.. Because the test server was restarted a few days ago, and then I did some other work on it. So it is suspected that the problem is port occupancy.. However.. Neither..

I had no choice, so I moved out the ultimate solution: reloading Hadoop and HBase. After the official configuration is completed. HBase is miraculously good..

I once suspected that it was my configuration.. However.. Neither..

Finally found a solution on the Internet, because Hadoop is in a safe mode. So HBase operation will be abnormal. I’m not sure how it works. The solution is to manually exit safe mode

./hadoop dfsadmin -safemode leave 

Then restart HBase and solve the problem