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kube-capacity
This is a simple CLI that provides an overview of the resource requests, limits, and utilization in a Kubernetes cluster. It attempts to combine the best parts of the output from kubectl top and kubectl describe into an easy to use CLI focused on cluster resources.
Installation
Go binaries are automatically built with each release by GoReleaser. These can be accessed on the GitHub releases page for this project.
Homebrew
This project can be installed with Homebrew:
brew tap robscott/tap
brew install robscott/tap/kube-capacity
Krew
This project can be installed with Krew:
kubectl krew install resource-capacity
Usage
By default, kube-capacity will output a list of nodes with the total CPU and Memory resource requests and limits for all the pods running on them. For clusters with more than one node, the first line will also include cluster wide totals. That output will look something like this:
kube-capacity
NODE CPU REQUESTS CPU LIMITS MEMORY REQUESTS MEMORY LIMITS
* 560m (28%) 130m (7%) 572Mi (9%) 770Mi (13%)
example-node-1 220m (22%) 10m (1%) 192Mi (6%) 360Mi (12%)
example-node-2 340m (34%) 120m (12%) 380Mi (13%) 410Mi (14%)
Including Pods
For more detailed output, kube-capacity can include pods in the output. When -p or --pods are passed to kube-capacity, it will include pod specific output that looks like this:
kube-capacity --pods
NODE NAMESPACE POD CPU REQUESTS CPU LIMITS MEMORY REQUESTS MEMORY LIMITS
* * * 560m (28%) 780m (38%) 572Mi (9%) 770Mi (13%)
example-node-1 * * 220m (22%) 320m (32%) 192Mi (6%) 360Mi (12%)
example-node-1 kube-system metrics-server-lwc6z 100m (10%) 200m (20%) 100Mi (3%) 200Mi (7%)
example-node-1 kube-system coredns-7b5bcb98f8 120m (12%) 120m (12%) 92Mi (3%) 160Mi (5%)
example-node-2 * * 340m (34%) 460m (46%) 380Mi (13%) 410Mi (14%)
example-node-2 kube-system kube-proxy-3ki7 200m (20%) 280m (28%) 210Mi (7%) 210Mi (7%)
example-node-2 tiller tiller-deploy 140m (14%) 180m (18%) 170Mi (5%) 200Mi (7%)
Including Utilization
To help understand how resource utilization compares to configured requests and limits, kube-capacity can include utilization metrics in the output. It's important to note that this output relies on metrics-server functioning correctly in your cluster. When -u or --util are passed to kube-capacity, it will include resource utilization information that looks like this:
kube-capacity --util
NODE CPU REQUESTS CPU LIMITS CPU UTIL MEMORY REQUESTS MEMORY LIMITS MEMORY UTIL
* 560m (28%) 130m (7%) 40m (2%) 572Mi (9%) 770Mi (13%) 470Mi (8%)
example-node-1 220m (22%) 10m (1%) 10m (1%) 192Mi (6%) 360Mi (12%) 210Mi (7%)
example-node-2 340m (34%) 120m (12%) 30m (3%) 380Mi (13%) 410Mi (14%) 260Mi (9%)
Displaying Available Resources
To more clearly see the total available resources on the node it is possible to pass the --available option
to kube-capacity, which will give output in the following format
kube-capacity --available
NODE CPU REQUESTS CPU LIMITS MEMORY REQUESTS MEMORY LIMITS
* 560/2000m 130/2000m 572/5923Mi 770/5923Mi
example-node-1 220/1000m 10/1000m 192/3200Mi 360/3200Mi
example-node-2 340/1000m 120/1000m 380/2923Mi 410/2923Mi
Including Pods and Utilization
For more detailed output, kube-capacity can include both pods and resource utilization in the output. When --util and --pods are passed to kube-capacity, it will result in a wide output that looks like this:
kube-capacity --pods --util
NODE NAMESPACE POD CPU REQUESTS CPU LIMITS CPU UTIL MEMORY REQUESTS MEMORY LIMITS MEMORY UTIL
* * * 560m (28%) 780m (38%) 340m (17%) 572Mi (9%) 770Mi (13%) 470Mi (8%)
example-node-1 * * 220m (22%) 320m (32%) 160m (16%) 192Mi (6%) 360Mi (12%) 210Mi (7%)
example-node-1 kube-system metrics-server-lwc6z 100m (10%) 200m (20%) 70m (7%) 100Mi (3%) 200Mi (7%) 120Mi (4%)
example-node-1 kube-system coredns-7b5bcb98f8 120m (12%) 120m (12%) 90m (9%) 92Mi (3%) 160Mi (5%) 90Mi (3%)
example-node-2 * * 340m (34%) 460m (46%) 180m (18%) 380Mi (13%) 410Mi (14%) 260Mi (9%)
example-node-2 kube-system kube-proxy-3ki7 200m (20%) 280m (28%) 110m (11%) 210Mi (7%) 210Mi (7%) 120Mi (4%)
example-node-2 tiller tiller-deploy 140m (14%) 180m (18%) 70m (7%) 170Mi (6%) 200Mi (7%) 140Mi (5%)
It's worth noting that utilization numbers from pods will likely not add up to the total node utilization numbers. Unlike request and limit numbers where node and cluster level numbers represent a sum of pod values, node metrics come directly from metrics-server and will likely include other forms of resource utilization.
Sorting
To highlight the nodes, pods, and containers with the highest metrics, you can sort by a variety of columns:
kube-capacity --util --sort cpu.util
NODE CPU REQUESTS CPU LIMITS CPU UTIL MEMORY REQUESTS MEMORY LIMITS MEMORY UTIL
* 560m (28%) 130m (7%) 40m (2%) 572Mi (9%) 770Mi (13%) 470Mi (8%)
example-node-2 340m (34%) 120m (12%) 30m (3%) 380Mi (13%) 410Mi (14%) 260Mi (9%)
example-node-1 220m (22%) 10m (1%) 10m (1%) 192Mi (6%) 360Mi (12%) 210Mi (7%)
Note Starting in v0.7.4 you can append
.percentageto sort by percentage. For example,kube-capacity --util --sort cpu.util.percentage.
Displaying Pod Count
To display the pod count of each node and the whole cluster, you can pass --pod-count argument:
$ kube-capacity --pod-count
NODE CPU REQUESTS CPU LIMITS MEMORY REQUESTS MEMORY LIMITS POD COUNT
* 950m (2%) 200m (0%) 284Mi (0%) 284Mi (0%) 10/220
minikube 850m (5%) 100m (0%) 231Mi (1%) 231Mi (1%) 8/110
minikube-m02 100m (0%) 100m (0%) 53Mi (0%) 53Mi (0%) 2/110
Filtering By Labels
For more advanced usage, kube-capacity also supports filtering by pod, namespace, and/or node labels. The following examples show how to use these filters:
kube-capacity --pod-labels app=nginx
kube-capacity --namespace default
kube-capacity --namespace-labels team=api
kube-capacity --node-labels kubernetes.io/role=node
Filtering By Node Taints
Kube-capacity supports advanced filtering by taints. Users can filter in and filter out taints within the same expression. The following examples show how to use node taint filters:
kube-capacity --node-taints special=true:NoSchedule
kube-capacity --node-taints special:NoSchedule
These will return only special nodes.
kube-capacity --node-taints special=true:NoSchedule-
kube-capacity --node-taints special:NoSchedule-
These will filter out special nodes and return only unspecial nodes.
kube-capacity --node-taints special=true:NoSchedule,old-hardware:NoSchedule-
This will return special nodes that are not tainted with old-hardware:NoSchedule. In other words, display the special nodes but don't display the ones that are running on old hardware.
kube-capacity --no-taint
This will filter out all nodes with taints.
JSON and YAML Output
By default, kube-capacity will provide output in a table format. To view this data in JSON or YAML format, the output flag can be used. Here are some sample commands:
kube-capacity --pods --output json
kube-capacity --pods --containers --util --output yaml
CSV and TSV Output
If you would like the data in a comma or tab separated file to make importing the data into a spreadsheet easier the output flag has options for those as well. Here are some sample commands:
kube-capacity --pods --output csv
kube-capacity --pods --containers --util --output tsv
Note: the
--availableflag is ignored with these two choices as the values can be derived within a spreadsheet
Flags Supported
--as string user to impersonate command with
--as-group string group to impersonate command with
-c, --containers includes containers in output
--context string context to use for Kubernetes config
-h, --help help for kube-capacity
--kubeconfig string kubeconfig file to use for Kubernetes config
-n, --namespace string only include pods from this namespace
--namespace-labels string labels to filter namespaces with
--no-taint exclude nodes with taints
--node-labels string labels to filter nodes with
-o, --output string output format for information
(supports: [table json yaml csv tsv])
(default "table")
-a, --available includes quantity available instead of percentage used (ignored with csv or tsv output types)
-t, --node-taints taints to filter nodes with
-l, --pod-labels string labels to filter pods with
-p, --pods includes pods in output
--sort string attribute to sort results by (supports:
[cpu.util cpu.request cpu.limit mem.util mem.request mem.limit cpu.util.percentage
cpu.request.percentage cpu.limit.percentage mem.util.percentage mem.request.percentage
mem.limit.percentage name])
(default "name")
-u, --util includes resource utilization in output
--pod-count includes pod counts for each of the nodes and the whole cluster
Prerequisites
Any commands requesting cluster utilization are dependent on metrics-server running on your cluster. If it's not already installed, you can install it with the official helm chart.
Similar Projects
There are already some great projects out there that have similar goals.
- kube-resource-report: generates HTML/CSS report for resource requests and limits across multiple clusters.
- kubetop: a CLI similar to top for Kubernetes, focused on resource utilization (not requests and limits).
Contributors
Although this project was originally developed by robscott, there have been some great contributions from others:
License
Apache License 2.0