Coredns is a fast and flexible, cloud native DNS server, written in Go programing language
Configuration of coredns check is stored k8s.ini file in conf directory.
Install
cd ${OE_AGENT_HOME}/checks_enabled
ln -s ../checks_available/check_coredns.py ./
Configure
If you are using default installation of ethd service, no additional configuration is needed.
If you need to monitor etc in non default location, edit conf/k8s.ini section coredns and set metrics parameter with value matching your needs.
Before enabling check_coredns module you should enable metrics plugin at Coredns.
Snippet above is an example of how metrics interface can be enabled in coredns
{
prometheus localhost:9253
}
When config file is changes , you should restart coredns daemon to apply new settings.
The metrics path at coredns is fixed to /metrics so make sure full URL of coredns metrics interface is written in conf/k8s.ini
[coredns]
metrics : http://127.0.0.1:9253/metrics
Restart
${OE_AGENT_HOME}/oddeye.sh restart
Provides
| Name | Description | Type | Unit |
|---|---|---|---|
| coredns_go_gc_duration_seconds_count | A summary of the GC invocation durations. | counter | Seconds |
| coredns_go_gc_duration_seconds_sum | A summary of the GC invocation durations. | sum | Seconds |
| coredns_go_goroutines | Number of goroutines that currently exist. | gauge | None |
| coredns_go_memstats_alloc_bytes | Number of bytes allocated and still in use. | gauge | Bytes |
| coredns_go_memstats_alloc_bytes_total | Number of bytes allocated and still in use. | total | Bytes |
| coredns_go_memstats_buck_hash_sys_bytes | Number of bytes used by the profiling bucket hash table. | gauge | Bytes |
| coredns_go_memstats_frees_total | Total number of frees. | counter | None |
| coredns_go_memstats_gc_cpu_fraction | The fraction of this program's available CPU time used by the GC since the program started. | gauge | None |
| coredns_go_memstats_gc_sys_bytes | Number of bytes used for garbage collection system metadata. | gauge | Bytes |
| coredns_go_memstats_heap_alloc_bytes | Number of heap bytes allocated and still in use. | gauge | Bytes |
| coredns_go_memstats_heap_idle_bytes | Number of heap bytes waiting to be used. | gauge | Bytes |
| coredns_go_memstats_heap_inuse_bytes | Number of heap bytes that are in use. | gauge | Bytes |
| coredns_go_memstats_heap_objectsNumber of allocated objects. | gauge | integer | |
| coredns_go_memstats_heap_released_bytes | Number of heap bytes released to OS. | gauge | Bytes |
| coredns_go_memstats_heap_sys_bytes | Number of heap bytes obtained from system. | gauge | Bytes |
| coredns_go_memstats_last_gc_time_seconds | Number of seconds since 1970 of last garbage collection. | gauge | Seconds |
| coredns_go_memstats_lookups_total | Total number of pointer lookups. | counter | None |
| coredns_go_memstats_mallocs_total | Total number of mallocs. | counter | None |
| coredns_go_memstats_mcache_inuse_bytes | Number of bytes in use by mcache structures. | gauge | Bytes |
| coredns_go_memstats_mcache_sys_bytes | Number of bytes used for mcache structures obtained from system. | gauge | Bytes |
| coredns_go_memstats_mspan_inuse_bytes | Number of bytes in use by mspan structures. | gauge | Bytes |
| coredns_go_memstats_mspan_sys_bytes | Number of bytes used for mspan structures obtained from system. | gauge | Bytes |
| coredns_go_memstats_next_gc_bytes | Number of heap bytes when next garbage collection will take place. | gauge | Bytes |
| coredns_go_memstats_other_sys_bytes | Number of bytes used for other system allocations. | gauge | Bytes |
| coredns_go_memstats_stack_inuse_bytes | Number of bytes in use by the stack allocator. | gauge | Bytes |
| coredns_go_memstats_stack_sys_bytes | Number of bytes obtained from system for stack allocator. | gauge | Bytes |
| coredns_go_memstats_sys_bytes | Number of bytes obtained from system. | gauge | Bytes |
| coredns_go_threads | Number of OS threads created. | gauge | None |
| coredns_health_request_duration_seconds_count | Time each request took. | counter | Seconds |
| coredns_health_request_duration_seconds_sum | Time each request took. | sum | Seconds |
| coredns_panic_count_total | A metrics that counts the number of panics. | counter | None |
| coredns_process_cpu_seconds_total | Total user and system CPU time spent in seconds. | counter | Seconds |
| coredns_process_max_fds | Maximum number of open file descriptors. | gauge | None |
| coredns_process_open_fds | Number of open file descriptors. | gauge | None |
| coredns_process_resident_memory_bytes | Resident memory size in bytes. | gauge | Bytes |
| coredns_process_start_time_seconds | Start time of the process since unix epoch in seconds. | gauge | Seconds |
| coredns_process_virtual_memory_bytes | Virtual memory size in bytes. | gauge | Bytes |
| coredns_process_virtual_memory_max_bytes | Maximum amount of virtual memory available in bytes. | gauge | Bytes |