Kubernetes resources

Node resources

https://github.com/kubernetes/kubernetes/issues/17512

kubectl describe nodes | grep 'Name:\|Allocated' -A 5 | grep 'Name\|memory'

Pod requests and limits

https://blog.kubecost.com/blog/requests-and-limits/#our-solution

Calculate resource usage of pods

Current Cpu/Mem usage:

$ kubectl -n mastodon top pod -l app.kubernetes.io/name=elasticsearch --sum=true

The equivalent prometheus query for the above kubectl cmd:

export MATCH='namespace="mastodon", pod=~".*elasticsearch.*"

• Be aware: image!="" for memory queries does make a difference !

Query	CPU (mil cores)	Mem (Mb)
Current metrics	sum(node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate{$MATCH}) by (pod)*1024	sum(container_memory_working_set_bytes{$MATCH, image!=''}/1024^2) by (pod)
Average resource usage over time	sum(rate(container_cpu_usage_seconds_total{$MATCH}[1w])) by (pod)*1024	avg_over_time(sum(container_memory_working_set_bytes{namespace="mastodon", pod=~".*elasticsearch.*", image!=""}) by (pod)[1w:])/1024^2
Total sum over time	sum(rate(container_cpu_usage_seconds_total{$MATCH}[1w]))*1024	sum(avg_over_time(sum(container_memory_working_set_bytes{$MATCH})[1w:]))/1024^2