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kustomize/cmd/config/docs/tutorials/configuration-basics.md
Phillip Wittrock 701c217791 Refactor kustomize config command structure
- Create cfg, fn, live parent commands
2020-06-06 08:50:41 -07:00

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## Configuration Basics
### Synopsis
`kustomize cfg` provides tools for working with local configuration directories.
First fetch a bundle of configuration to your local file system from the
Kubernetes examples repository.
git clone https://github.com/kubernetes/examples/
cd examples/
### `tree` -- view Resources and directory structure
`tree` can be used to summarize the collection of Resources in a directory:
$ kustomize cfg tree mysql-wordpress-pd/
mysql-wordpress-pd
├── [gce-volumes.yaml] v1.PersistentVolume wordpress-pv-1
├── [gce-volumes.yaml] v1.PersistentVolume wordpress-pv-2
├── [local-volumes.yaml] v1.PersistentVolume local-pv-1
├── [local-volumes.yaml] v1.PersistentVolume local-pv-2
├── [mysql-deployment.yaml] v1.PersistentVolumeClaim mysql-pv-claim
├── [mysql-deployment.yaml] apps/v1.Deployment wordpress-mysql
├── [mysql-deployment.yaml] v1.Service wordpress-mysql
├── [wordpress-deployment.yaml] apps/v1.Deployment wordpress
├── [wordpress-deployment.yaml] v1.Service wordpress
└── [wordpress-deployment.yaml] v1.PersistentVolumeClaim wp-pv-claim
`tree` may be provided flags to print the Resource field values. `tree` has a number of built-in
supported fields, and may also print arbitrary values using the `--field` flag to specify a field
path.
$ kustomize cfg tree mysql-wordpress-pd/ --name --image --replicas --ports
mysql-wordpress-pd
├── [gce-volumes.yaml] PersistentVolume wordpress-pv-1
├── [gce-volumes.yaml] PersistentVolume wordpress-pv-2
├── [local-volumes.yaml] PersistentVolume local-pv-1
├── [local-volumes.yaml] PersistentVolume local-pv-2
├── [mysql-deployment.yaml] PersistentVolumeClaim mysql-pv-claim
├── [mysql-deployment.yaml] Deployment wordpress-mysql
│   └── spec.template.spec.containers
│   └── 0
│   ├── name: mysql
│   ├── image: mysql:5.6
│   └── ports: [{name: mysql, containerPort: 3306}]
├── [mysql-deployment.yaml] Service wordpress-mysql
│   └── spec.ports: [{port: 3306}]
├── [wordpress-deployment.yaml] Deployment wordpress
│   └── spec.template.spec.containers
│   └── 0
│   ├── name: wordpress
│   ├── image: wordpress:4.8-apache
│   └── ports: [{name: wordpress, containerPort: 80}]
├── [wordpress-deployment.yaml] Service wordpress
│   └── spec.ports: [{port: 80}]
└── [wordpress-deployment.yaml] PersistentVolumeClaim wp-pv-claim
`tree` can also be used with `kubectl get` to print cluster Resources using OwnersReferences
to build the tree structure.
kubectl apply -R -f cockroachdb/
kubectl get all -o yaml | kustomize cfg tree --graph-structure owners --name --image --replicas
.
├── [Resource] Deployment wp/wordpress
│   ├── spec.replicas: 1
│   ├── spec.template.spec.containers
│   │   └── 0
│   │   ├── name: wordpress
│   │   └── image: wordpress:4.8-apache
│   └── [Resource] ReplicaSet wp/wordpress-76b5d9f5c8
│   ├── spec.replicas: 1
│   ├── spec.template.spec.containers
│   │   └── 0
│   │   ├── name: wordpress
│   │   └── image: wordpress:4.8-apache
│   └── [Resource] Pod wp/wordpress-76b5d9f5c8-g656w
│   └── spec.containers
│   └── 0
│   ├── name: wordpress
│   └── image: wordpress:4.8-apache
├── [Resource] Service wp/wordpress
...
### `cat` -- view the full collection of Resources
$ kustomize cfg cat mysql-wordpress-pd/
apiVersion: v1
kind: PersistentVolume
metadata:
name: wordpress-pv-1
annotations:
config.kubernetes.io/path: gce-volumes.yaml
spec:
accessModes:
- ReadWriteOnce
capacity:
storage: 20Gi
gcePersistentDisk:
fsType: ext4
pdName: wordpress-1
---
apiVersion: v1
...
`cat` prints the raw package Resources. This may be used to pipe them to other tools
such as `kubectl apply -f -`.
## `fmt` -- format the Resources for a directory (like go fmt for Kubernetes Resources)
`fmt` formats the Resource Configuration by applying a consistent style, including
ordering of fields and indentation.
$ kustomize cfg fmt mysql-wordpress-pd/
Run `git diff` and see the changes that have been applied.
### `grep` -- search for Resources by field values
`grep` prints Resources matching some field value. The Resources are annotated with their
file source so they can be piped to other commands without losing this information.
$ kustomize cfg grep "metadata.name=wordpress" wordpress/
apiVersion: v1
kind: Service
metadata:
name: wordpress
labels:
app: wordpress
annotations:
config.kubernetes.io/path: wordpress-deployment.yaml
spec:
ports:
- port: 80
selector:
app: wordpress
tier: frontend
type: LoadBalancer
---
...
- list elements may be indexed by a field value using list[field=value]
- '.' as part of a key or value may be escaped as '\.'
$ kustomize cfg grep "spec.status.spec.containers[name=nginx].image=mysql:5\.6" wordpress/
apiVersion: apps/v1 # for k8s versions before 1.9.0 use apps/v1beta2 and before 1.8.0 use extensions/v1beta1
kind: Deployment
metadata:
name: wordpress-mysql
labels:
app: wordpress
spec:
selector:
matchLabels:
app: wordpress
tier: mysql
template:
metadata:
labels:
app: wordpress
tier: mysql
...
`grep` may be used with kubectl to search for Resources in a cluster matching a value.
kubectl get all -o yaml | kustomize cfg grep "spec.replicas>0" | kustomize cfg tree --replicas
.
└──
├── [.] Deployment wp/wordpress
│   └── spec.replicas: 1
├── [.] ReplicaSet wp/wordpress-76b5d9f5c8
│   └── spec.replicas: 1
├── [.] Deployment wp/wordpress-mysql
│   └── spec.replicas: 1
└── [.] ReplicaSet wp/wordpress-mysql-f9447f458
└── spec.replicas: 1
### Error handling
If there is an error parsing the Resource configuration, kustomize will print an error with the file.
$ kustomize cfg grep "spec.template.spec.containers[name=\.*].resources.limits.cpu>1.0" ./staging/ | kustomize cfg tree --name --resources
Error: staging/persistent-volume-provisioning/quobyte/quobyte-admin-secret.yaml: [0]: yaml: unmarshal errors:
line 13: mapping key "type" already defined at line 9
Here the `staging/persistent-volume-provisioning/quobyte/quobyte-admin-secret.yaml` has a malformed
Resource. Remove the malformed Resources:
rm staging/persistent-volume-provisioning/quobyte/quobyte-admin-secret.yaml
rm staging/storage/vitess/etcd-service-template.yaml
When developing -- to get a stack trace for where an error was encountered,
use the `--stack-trace` flag:
$ kustomize cfg grep "spec.template.spec.containers[name=\.*].resources.limits.cpu>1.0" ./staging/ --stack-trace
go/src/sigs.k8s.io/kustomize/kyaml/yaml/types.go:260 (0x4d35c86)
(*RNode).GetMeta: return m, errors.Wrap(err)
go/src/sigs.k8s.io/kustomize/kyaml/kio/byteio_reader.go:130 (0x4d3e099)
(*ByteReader).Read: meta, err := node.GetMeta()
...
### Combine `grep` and `tree`
`grep` and `tree` may be combined to perform queries against configuration.
Query for `replicas`:
$ kustomize cfg grep "spec.replicas>5" ./ | kustomize cfg tree --replicas
.
├── staging/sysdig-cloud
│   └── [sysdig-rc.yaml] ReplicationController sysdig-agent
│   └── spec.replicas: 100
└── staging/volumes/vsphere
└── [simple-statefulset.yaml] StatefulSet web
└── spec.replicas: 14
Query for `resource.limits`
$ kustomize cfg grep "spec.template.spec.containers[name=\.*].resources.limits.memory>0" ./ | kustomize cfg tree --resources
.
├── cassandra
│   └── [cassandra-statefulset.yaml] StatefulSet cassandra
│   └── spec.template.spec.containers
│   └── 0
│   └── resources: {limits: {cpu: "500m", memory: 1Gi}, requests: {cpu: "500m", memory: 1Gi}}
├── staging/selenium
│   ├── [selenium-hub-deployment.yaml] Deployment selenium-hub
│   │   └── spec.template.spec.containers
│   │   └── 0
│   │   └── resources: {limits: {memory: 1000Mi, cpu: ".5"}}
│   ├── [selenium-node-chrome-deployment.yaml] Deployment selenium-node-chrome
│   │   └── spec.template.spec.containers
│   │   └── 0
│   │   └── resources: {limits: {memory: 1000Mi, cpu: ".5"}}
│   └── [selenium-node-firefox-deployment.yaml] Deployment selenium-node-firefox
│   └── spec.template.spec.containers
│   └── 0
│   └── resources: {limits: {memory: 1000Mi, cpu: ".5"}}
...
### Inverting `grep`
The `grep` results may be inverted with the `-v` flag and used to find Resources that don't
match a query.
Find Resources that have an image specified, but the image doesn't have a tag:
$ kustomize cfg grep "spec.template.spec.containers[name=\.*].name=\.*" ./ | kustomize cfg grep "spec.template.spec.containers[name=\.*].image=\.*:\.*" -v | kustomize cfg tree --image --name
.
├── staging/newrelic
│   ├── [newrelic-daemonset.yaml] DaemonSet newrelic-agent
│   │   └── spec.template.spec.containers
│   │   └── 0
│   │   ├── name: newrelic
│   │   └── image: newrelic/nrsysmond
│   └── staging/newrelic-infrastructure
│   └── [newrelic-infra-daemonset.yaml] DaemonSet newrelic-infra-agent
│   └── spec.template.spec.containers
│   └── 0
│   ├── name: newrelic
│   └── image: newrelic/infrastructure
├── staging/nodesjs-mongodb
│   ├── [mongo-controller.yaml] ReplicationController mongo-controller
│   │   └── spec.template.spec.containers
│   │   └── 0
│   │   ├── name: mongo
│   │   └── image: mongo
│   └── [web-controller.yaml] ReplicationController web-controller
│   └── spec.template.spec.containers
│   └── 0
│   ├── name: web
│   └── image: <YOUR-CONTAINER>
...