By default, all stats are returned. You can limit this by combining any of
indices, os, process, jvm, network, transport, http, fs, breaker and
thread_pool. With the metric parameter you can select zero or more of:
indices Indices stats about size, document count, indexing and
deletion times, search times, field cache size, merges and flushes
os retrieve information that concern the operating system
fs File system information, data path, free disk space,
read/write stats
http HTTP connection information
jvm JVM stats, memory pool information, garbage collection,
buffer pools
network TCP information
os Operating system stats, load average, cpu, mem, swap
process Process statistics, memory consumption, cpu usage, open
file descriptors
thread_pool Statistics about each thread pool, including current
size, queue and rejected tasks
transport Transport statistics about sent and received bytes in
cluster communication
breaker Statistics about the field data circuit breaker