Kubernetes metrics to watch for capacity management

k8s_metrics.md

Nice and eazy Metrics

• Information about Node:

# Gauge type metric

# CPU capacity <cores>
kube_node_status_capacity{resource="cpu"}

# Memory capacity <bytes>
kube_node_status_capacity{resource="memory"}

• Information about Pod:

# Gauge type metric:
kube_pod_container_info

• The number of requests/limits resource by a container:

# Gauge type metric:
kube_pod_container_resource_requests
kube_pod_container_resource_limits

• Current Working Set(set of memory pages touched recently by the threads in the process) in bytes, aka OOM killer:

# Gauge type metric:
container_memory_working_set_bytes

• Cumultaive CPU time (user time +system time) consumed in seconds:

# Counter type metric:
container_cpu_usage_seconds_total

PromQL query

• Gauge/stat for no of pods in each namespace:

sum(kube_pod_info) by (namespace)

• Containers without Memory/CPU limits per namespace:

# without CPU limts
sum by (namespace)(count by (namespace,pod,container)(kube_pod_container_info{container!=""}) unless sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="CPU"}))

# without Memory limits
sum by (namespace)(count by (namespace,pod,container)(kube_pod_container_info{container!=""}) unless sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="memory"}))

• Containers whose CPU is are close to limits:

(sum by (namespace,pod,container)(rate(container_cpu_usage_seconds_total{container!=""}[5m])) / sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="cpu"})) > 0.8

• Containers whose Memory usage is close to limits:

(sum by (namespace,pod,container)(container_memory_usage_bytes{container!=""}) / sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="memory"})) > 0.8

• Top 10 containers without limits using CPU:

topk(10,sum by (namespace,pod,container)(rate(container_cpu_usage_seconds_total{container!=""}[5m])) unless sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="cpu"}))

• Top 10 containers without limits using Memory:

topk(10,sum by (namespace,pod,container)(container_memory_usage_bytes{container!=""}) unless sum by (namespace,pod,container)(kube_pod_container_resource_limits{resource="memory"}))

• Memory requests and limits:

# pod == label_values(pod)
kube_pod_container_resource_requests{pod="$pod", resource="memory"}
kube_pod_container_resource_limits{pod="$pod", resource="memory"}

• Memory usage:

# pod == label_values(pod)
container_memory_working_set_bytes{name!~"POD",pod="$pod"}