kuota-calc

README

[!NOTE] This is a fork of druppelt/kuota-calc that adds some features:

• added support for HorizontalPodAutoscaler
• added JSON output format
• added suppression of warning about unsupported kinds

kuota-calc

Simple utility to calculate the maximum needed resource quota for deployment(s). kuota-calc takes the deployment strategy, replicas and all containers into account, see supported-resources for a list of kubernetes resources which are currently supported by kuota-calc.

Motivation

In shared environments such as kubernetes it is always a good idea to isolate/constrain different workloads to prevent them from interfering each other. Kubernetes provides Resource Quotas to limit compute, storage and object resources of namespaces.

Calculating the needed compute resources can be a bit challenging (especially with large and complex deployments) because we must respect certain settings/defaults like the deployment strategy, number of replicas and so on. This is where kuota-calc can help you, it calculates the maximum needed resource quota in order to be able to start a deployment of all resources at the same time by respecting deployment strategies, replicas and so on.

Example

Get a detailed report of all resources, their max required quota and a total.

$ cat examples/deployment.yaml | kuota-calc -detailed
Version    Kind           Name     Replicas    Strategy         MaxReplicas    CPURequest    CPULimit    MemoryRequest    MemoryLimit    
apps/v1    Deployment     myapp    10          RollingUpdate    13             3250m         6500m       832Mi            3328Mi         
apps/v1    StatefulSet    myapp    3           RollingUpdate    3              750m          3           6Gi              12Gi           

Table and Total assuming simultaneous rollout of all resources

Total
CPU Request: 4
CPU Limit: 9500m
Memory Request: 6976Mi
Memory Limit: 15616Mi

For comparison, here the simultaneous rollout is limited to zero resources, so you get the required quotas to just run, but not deploy the applications.

$ cat examples/deployment.yaml | kuota-calc --max-rollouts=0
CPU Request: 3250m
CPU Limit: 8
Memory Request: 6784Mi
Memory Limit: 14848Mi

To calc usage for deploymentConfigs, deployments and statefulSets deployed in an openshift cluster:

$ oc get dc,sts,deploy -o json | yq -p=json -o=yaml '.items[] | split_doc' | kuota-calc --detailed
Warning: apps.openshift.io/v1 DeploymentConfig is deprecated in v4.14+, unavailable in v4.10000+
Version                 Kind                Name                        Replicas    Strategy         MaxReplicas    CPURequest    CPULimit    MemoryRequest    MemoryLimit
apps.openshift.io/v1    DeploymentConfig    my-app-1                    0           Recreate         0              0             0           0                0
apps.openshift.io/v1    DeploymentConfig    my-app-2                    1           Recreate         1              1250m         1700m       500Mi            500Mi
apps/v1                 StatefulSet         my-app-3                    1           RollingUpdate    1              150m          1100m       2200Mi           2200Mi
apps/v1                 Deployment          my-app-4                    1           RollingUpdate    2              100m          200m        100Mi            512Mi

Total
CPU Request: 1500m
CPU Limit: 3
Memory Request: 2800Mi
Memory Limit: 3212Mi

Installation

Pre-compiled statically linked binaries are available on the releases page.

kuota-calc can either be used as a kubectl plugin or invoked directly. If you intend to use kuota-calc as a kubectl plugin, simply place the binary anywhere in $PATH named kubectl-kuota_calc with execute permissions. For further information, see the official documentation on kubectl plugins here.

currently the kubectl plugin is not released for this fork

supported k8s and os resources

kuota-calc is still a work-in progress, there are plans to support more k8s resources (see #5 for more info).

Currently supported:

• apps.openshift.io/v1 DeploymentConfig
• apps/v1 Deployment
• apps/v1 StatefulSet
• apps/v1 DaemonSet
• batch/v1 CronJob
• batch/v1 Job
• v1 Pod
• autoscaling/v2 HorizontalPodAutoscaler

known limitation

• CronJobs: the cron concurrencyPolicy is not considered, a CronJob is treated as a single Pod (#18)
• DaemonSet: neither node count nor UpdateStrategy are considered. Treated as a single Pod. (#21)

Documentation

Overview

Package main is the entrypoint for the cli