Marvel and what it is
With marvel you can get an overview of the state of your elasticsearch cluster. When problems arise you can drill down to all aspects of the nodes in your cluster as well as the indexes.
If the network is connected:
cd /usr/share/elasticsearch bin/plugin -i elasticsearch/marvel/latest
Marvel uses the excellent api that elasticsearch itself is providing to get data about your cluster. If you have acces to a cluster you should try out how much information you can obtain. Some of the interesting urls that you can use are:
A very easy way to try it out is to use the sense tool. You have acces to this tool from the marvel screen. Go to Marvel Dashboards and select the sense tab. The result is the following screen.
The following screen gives an idea of the main screen of marvel. Here you see the overview. Colours indicate problem. Using the overview you can drill down easily. In the top you see the totals for the complete cluster, the number of documents, queries and inserts.
The following image shows the node overview, you can see we have three nodes (three pi's). You can also see that the pi-wit is handling the marvel index. This is having a hard time keeping up. You can also see that elasticsearch prefers more disk space, therefore Disk Free Space is red for all nodes.
Than the final image I want to show from the overview desktop is the index overview. Here you can see that I do not use the index mymusic yet, it does not have documents.
The final thing I want to show is drilling down, if you select two nodes in the node overview and push the Dashboard button. You go to the screen where you can request very detailed information about the nodes.
So how was this possible. The next section discusses the steps to install the pi's with elasticsearch.