Storm Management and Maintenance - Real-time Analytics with Storm and Cassandra - page 198

• Column one has the Id field for the supervisors, and column two has the names of
the hosts field that have supervisor processes running.
• Column three captures the amount of time the supervisor has been running for.
• Columns five and six capture the number of slots available on the supervisor and
the number of slots used respectively. These two numbers provide a very import-
ant metric in terms of how many slots are available and how many are used. They
help us judge and understand what capacity the supervisors are operating at and
how much bandwidth they have to handle the scenarios of failures; for instance,
all my supervisors are operating at 100 percent capacity, so in that case, my
cluster can't handle any failures.
The following screenshot is captured from the Storm UI depicting supervisors and their
attributes:
The preceding section gives us details about the supervisor slots, timeouts, and so on.
These values are specified on storm.yaml , but can be verified from the UI. For ex-
ample, http:// ip of nimbus:8080 in my case is ht-
tp://10.4.2.122:8080 , and my UI process executes on the Nimbus machine that
has this IP: 10.4.2.122, as shown in the following screenshot: