I'm new to hadoop and also new to the sandbox of Hortonworks sandbox. I installed the sandbox and after a while of practicing, some components in the dashboard grayed out (as highlighted in the following pic) and are not able to execute anything on those grayed-out components. How can I bring those components back green status?
You need to click on each component then in top right hand corner you need to select actions > turn off maintenance mode. don't do it for secondary namenodes as that is there on purpose, this is a single node machine
thanks very much for your help. But when I click HDFS components, under "actions" dropdown list, there is no turn off maintenance mode listed.
I noticed that maybe it's a good idea to leave HDFS in maintenance mode ... otherwise you will get loads of underreplicated blocks error messages since there is only one node.
thanks. I was running a pig script. It was not responding anything for a very long time. Now I noticed that I need to wait for even longer for having the first log info.
For maintenance mode, you could always tun off the maintenance mode and enable the service manually. Some of the components are best left off when you don't really need them because some of them are really resource hogs. Generally, HDFS, MapReduce2, YARN and Hive should be green the makes most things working.