[[cat-nodes]]
== cat nodes

The `nodes` command shows the cluster topology.

["source","sh",subs="attributes,callouts"]
--------------------------------------------------
% curl 192.168.56.10:9200/_cat/nodes
SP4H 4727 192.168.56.30 9300 {version} {jdk} 72.1gb 35.4 93.9mb 79 239.1mb 0.45 3.4h d m Boneyard
_uhJ 5134 192.168.56.10 9300 {version} {jdk} 72.1gb 33.3 93.9mb 85 239.1mb 0.06 3.4h d * Athena
HfDp 4562 192.168.56.20 9300 {version} {jdk} 72.2gb 74.5 93.9mb 83 239.1mb 0.12 3.4h d m Zarek
--------------------------------------------------

The first few columns tell you where your nodes live.  For sanity it
also tells you what version of ES and the JVM each one runs.

["source","sh",subs="attributes,callouts"]
--------------------------------------------------
nodeId pid  ip            port version jdk
u2PZ   4234 192.168.56.30 9300 {version}   {jdk}
URzf   5443 192.168.56.10 9300 {version}   {jdk}
ActN   3806 192.168.56.20 9300 {version}   {jdk}
--------------------------------------------------


The next few give a picture of your heap, memory, and load.

[source,sh]
--------------------------------------------------
diskAvail heapPercent heapMax ramPercent  ramMax load
   72.1gb        31.3  93.9mb         81 239.1mb 0.24
   72.1gb        19.6  93.9mb         82 239.1mb 0.05
   72.2gb        64.9  93.9mb         84 239.1mb 0.12
--------------------------------------------------

The last columns provide ancillary information that can often be
useful when looking at the cluster as a whole, particularly large
ones.  How many master-eligible nodes do I have?  How many client
nodes?  It looks like someone restarted a node recently; which one was
it?

[source,sh]
--------------------------------------------------
uptime data/client master name
  3.5h d           m      Boneyard
  3.5h d           *      Athena
  3.5h d           m      Zarek
--------------------------------------------------

[float]
=== Columns

Below is an exhaustive list of the existing headers that can be
passed to `nodes?h=` to retrieve the relevant details in ordered
columns.  If no headers are specified, then those marked to Appear
by Default will appear. If any header is specified, then the defaults
are not used.

Aliases can be used in place of the full header name for brevity.
Columns appear in the order that they are listed below unless a
different order is specified (e.g., `h=pid,id` versus `h=id,pid`).

When specifying headers, the headers are not placed in the output
by default.  To have the headers appear in the output, use verbose
mode (`v`). The header name will match the supplied value (e.g.,
`pid` versus `p`).  For example:

["source","sh",subs="attributes,callouts"]
--------------------------------------------------
% curl 192.168.56.10:9200/_cat/nodes?v&h=id,ip,port,v,m
id   ip            port version m
pLSN 192.168.56.30 9300 {version}   m
k0zy 192.168.56.10 9300 {version}   m
6Tyi 192.168.56.20 9300 {version}   *
% curl 192.168.56.10:9200/_cat/nodes?h=id,ip,port,v,m
pLSN 192.168.56.30 9300 {version} m
k0zy 192.168.56.10 9300 {version} m
6Tyi 192.168.56.20 9300 {version} *
--------------------------------------------------

[cols="<,<,<,<,<",options="header",subs="normal"]
|=======================================================================
|Header |Alias |Appear by Default |Description |Example
|`id` |`nodeId` |No |Unique node ID |k0zy
|`pid` |`p` |No |Process ID |13061
|`host` |`h` |Yes |Host name |n1
|`ip` |`i` |Yes |IP address |127.0.1.1
|`port` |`po` |No |Bound transport port |9300
|`version` |`v` |No |Elasticsearch version |{version}
|`build` |`b` |No |Elasticsearch Build hash |5c03844
|`jdk` |`j` |No |Running Java version |1.8.0
|`disk.avail` |`d`, `disk`, `diskAvail` |No |Available disk space |1.8gb
|`heap.current` |`hc`, `heapCurrent` |No |Used heap |311.2mb
|`heap.percent` |`hp`, `heapPercent` |Yes |Used heap percentage |7
|`heap.max` |`hm`, `heapMax` |No |Maximum configured heap |1015.6mb
|`ram.current` |`rc`, `ramCurrent` |No |Used total memory |513.4mb
|`ram.percent` |`rp`, `ramPercent` |Yes |Used total memory percentage |47
|`ram.max` |`rm`, `ramMax` |No |Total memory |2.9gb
|`file_desc.current` |`fdc`, `fileDescriptorCurrent` |No |Used file
descriptors |123
|`file_desc.percent` |`fdp`, `fileDescriptorPercent` |Yes |Used file
descriptors percentage |1
|`file_desc.max` |`fdm`, `fileDescriptorMax` |No |Maximum number of file
descriptors |1024
|`load` |`l` |No |Most recent load average |0.22
|`uptime` |`u` |No |Node uptime |17.3m
|`node.role` |`r`, `role`, `dc`, `nodeRole` |Yes |Data node (d); Client
node (c) |d
|`master` |`m` |Yes |Current master (*); master eligible (m) |m
|`name` |`n` |Yes |Node name |Venom
|`completion.size` |`cs`, `completionSize` |No |Size of completion |0b
|`fielddata.memory_size` |`fm`, `fielddataMemory` |No |Used fielddata
cache memory |0b
|`fielddata.evictions` |`fe`, `fielddataEvictions` |No |Fielddata cache
evictions |0
|`filter_cache.memory_size` |`fcm`, `filterCacheMemory` |No |Used filter
cache memory |0b
|`filter_cache.evictions` |`fce`, `filterCacheEvictions` |No |Filter
cache evictions |0
|`flush.total` |`ft`, `flushTotal` |No |Number of flushes |1
|`flush.total_time` |`ftt`, `flushTotalTime` |No |Time spent in flush |1
|`get.current` |`gc`, `getCurrent` |No |Number of current get
operations |0
|`get.time` |`gti`, `getTime` |No |Time spent in get |14ms
|`get.total` |`gto`, `getTotal` |No |Number of get operations |2
|`get.exists_time` |`geti`, `getExistsTime` |No |Time spent in
successful gets |14ms
|`get.exists_total` |`geto`, `getExistsTotal` |No |Number of successful
get operations |2
|`get.missing_time` |`gmti`, `getMissingTime` |No |Time spent in failed
gets |0s
|`get.missing_total` |`gmto`, `getMissingTotal` |No |Number of failed
get operations |1
|`indexing.delete_current` |`idc`, `indexingDeleteCurrent` |No |Number
of current deletion operations |0
|`indexing.delete_time` |`idti`, `indexingDeleteTime` |No |Time spent in
deletions |2ms
|`indexing.delete_total` |`idto`, `indexingDeleteTotal` |No |Number of
deletion operations |2
|`indexing.index_current` |`iic`, `indexingIndexCurrent` |No |Number
of current indexing operations |0
|`indexing.index_time` |`iiti`, `indexingIndexTime` |No |Time spent in
indexing |134ms
|`indexing.index_total` |`iito`, `indexingIndexTotal` |No |Number of
indexing operations |1
|`merges.current` |`mc`, `mergesCurrent` |No |Number of current
merge operations |0
|`merges.current_docs` |`mcd`, `mergesCurrentDocs` |No |Number of
current merging documents |0
|`merges.current_size` |`mcs`, `mergesCurrentSize` |No |Size of current
merges |0b
|`merges.total` |`mt`, `mergesTotal` |No |Number of completed merge
operations |0
|`merges.total_docs` |`mtd`, `mergesTotalDocs` |No |Number of merged
documents |0
|`merges.total_size` |`mts`, `mergesTotalSize` |No |Size of current
merges |0b
|`merges.total_time` |`mtt`, `mergesTotalTime` |No |Time spent merging
documents |0s
|`percolate.current` |`pc`, `percolateCurrent` |No |Number of current
percolations |0
|`percolate.memory_size` |`pm`, `percolateMemory` |No |Memory used by
current percolations |0b
|`percolate.queries` |`pq`, `percolateQueries` |No |Number of
registered percolation queries |0
|`percolate.time` |`pti`, `percolateTime` |No |Time spent
percolating |0s
|`percolate.total` |`pto`, `percolateTotal` |No |Total percolations |0
|`refresh.total` |`rto`, `refreshTotal` |No |Number of refreshes |16
|`refresh.time` |`rti`, `refreshTime` |No |Time spent in refreshes |91ms
|`search.fetch_current` |`sfc`, `searchFetchCurrent` |No |Current fetch
phase operations |0
|`search.fetch_time` |`sfti`, `searchFetchTime` |No |Time spent in fetch
phase |37ms
|`search.fetch_total` |`sfto`, `searchFetchTotal` |No |Number of fetch
operations |7
|`search.open_contexts` |`so`, `searchOpenContexts` |No |Open search
contexts |0
|`search.query_current` |`sqc`, `searchFetchCurrent` |No |Current query
phase operations |0
|`search.query_time` |`sqti`, `searchFetchTime` |No |Time spent in query
phase |43ms
|`search.query_total` |`sqto`, `searchFetchTotal` |No |Number of query
operations |9
|`search.scroll_current` |`scc`, `searchScrollCurrent` |No |Open scroll contexts |2
|`search.scroll_time` |`scti`, `searchScrollTime` |No |Time scroll contexts held open|2m
|`search.scroll_total` |`scto`, `searchScrollTotal` |No |Completed scroll contexts |1
|`segments.count` |`sc`, `segmentsCount` |No |Number of segments |4
|`segments.memory` |`sm`, `segmentsMemory` |No |Memory used by
segments |1.4kb
|`segments.index_writer_memory` |`siwm`, `segmentsIndexWriterMemory` |No
|Memory used by index writer |18mb
|`segments.index_writer_max_memory` |`siwmx`, `segmentsIndexWriterMaxMemory` |No
|Maximum memory index writer may use before it must write buffered documents to a new segment |32mb
|`segments.version_map_memory` |`svmm`, `segmentsVersionMapMemory` |No
|Memory used by version map |1.0kb
|=======================================================================
