116 lines
3.6 KiB
Markdown
116 lines
3.6 KiB
Markdown
### Docker Info Example Plugin
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#### Description
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Let's say we want to use `check_http_json.py` to read from Docker's `/info` HTTP API endpoint with the following parameters:
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##### Connection information
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* Host = 127.0.0.1:4243
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* Path = /info
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##### Rules for "aliveness"
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* Verify that the key `Containers` exists in the outputted JSON
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* Verify that the key `IPv4Forwarding` has a value of `1`
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* Verify that the key `Debug` has a value less than or equal to `2`
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* Verify that the key `Images` has a value greater than or equal to `1`
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* If any of these criteria are not met, report a WARNING to Nagios
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##### Gather Metrics
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* Report value of the key `Containers` with a MinValue of 0 and a MaxValue of 1000 as performance data
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* Report value of the key `Images` as performance data
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* Report value of the key `NEventsListener` as performance data
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* Report value of the key `NFd` as performance data
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* Report value of the key `NGoroutines` as performance data
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* Report value of the key `SwapLimit` as performance data
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#### Service Definition
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`localhost.cfg`
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```
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define service {
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use local-service
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host_name localhost
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service_description Docker info status checker
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check_command check_docker
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}
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```
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#### Command Definition with Arguments
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`commands.cfg`
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```
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define command{
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command_name check_docker
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command_line /usr/bin/python /usr/local/nagios/libexec/plugins/check_http_json.py -H 127.0.0.1:4243 -p info -e Containers -q IPv4Forwarding,1 -w Debug,2:2 -c Images,1:1 -m Containers,0:250,0:500,0,1000 Images NEventsListener NFd NGoroutines SwapLimit
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}
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```
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#### Sample Output
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```
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OK: Status OK.|'Containers'=1;0;1000 'Images'=11;0;0 'NEventsListener'=3;0;0 'NFd'=10;0;0 'NGoroutines'=14;0;0 'SwapLimit'=1;0;0
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```
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### Docker Container Monitor Example Plugin
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`check_http_json.py` is generic enough to read and evaluate rules on any HTTP endpoint that returns JSON. In this example we'll get the status of a specific container using it's ID which camn be found by using the list containers endpoint (`curl http://127.0.0.1:4243/containers/json?all=1`).
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##### Connection information
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* Host = 127.0.0.1:4243
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* Path = /containers/2356e8ccb3de8308ccb16cf8f5d157bc85ded5c3d8327b0dfb11818222b6f615/json
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##### Rules for "aliveness"
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* Verify that the key `ID` exists and is equal to the value `2356e8ccb3de8308ccb16cf8f5d157bc85ded5c3d8327b0dfb11818222b6f615`
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* Verify that the key `State.Running` has a value of `True`
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#### Service Definition
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`localhost.cfg`
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```
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define service {
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use local-service
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host_name localhost
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service_description Docker container liveness check
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check_command check_my_container
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}
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```
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#### Command Definition with Arguments
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`commands.cfg`
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```
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define command{
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command_name check_my_container
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command_line /usr/bin/python /usr/local/nagios/libexec/plugins/check_http_json.py -H 127.0.0.1:4243 -p /containers/2356e8ccb3de8308ccb16cf8f5d157bc85ded5c3d8327b0dfb11818222b6f615/json -q ID,2356e8ccb3de8308ccb16cf8f5d157bc85ded5c3d8327b0dfb11818222b6f615 State.Running,True
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}
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```
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#### Sample Output
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```
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WARNING: Status check failed, reason: Value True for key State.Running did not match.
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```
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The plugin threw a warning because the Container ID I used on my system has the following State object:
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```
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u'State': {...
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u'Running': False,
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...
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```
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If I change the command to have the parameter -q parameter `State.Running,False`, the output becomes:
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```
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OK: Status OK.
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```
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