kenv
kenv is an environment file injector for Kubernetes resources.
kenv injects variables into Kubernetes resource documents by loading a list of files containing variables and modifying the resource document to include those values. This way, you can dynamically set environment variables without having to template your resource documents.
kenv supports referencing environment variables as:
Getting Started
Download kenv and run by passing a resource doc (YAML or JSON) to:
STDIN:
cat fixtures/deployment.yaml | ./kenv -v fixtures/vars.env
./kenv -v fixtures/vars.env < fixtures/deployment.yaml
or as a CLI Arg:
./kenv -v fixtures/vars.env fixtures/deployment.yaml
Usage
Usage: kenv [options] file
Examples:
kenv -v fixtures/vars.env fixtures/deployment.yaml
kenv -name nginx -v fixtures/vars.env -s fixtures/secrets.yml fixtures/deployment.yaml
cat fixtures/deployment.yaml | kenv -v fixtures/vars.env
Options:
-c value
Files containing variables to inject as ConfigMaps (repeatable)
-convert-keys
Convert ConfigMap keys to support k8s version < 1.4
-name string
Name to give the ConfigMap and Secret resources
-namespace string
Namespace to create the ConfigMap in (default "default")
-s value
Files containing variables to inject as Secrets (repeatable)
-v value
Files containing variables to inject as environment variables (repeatable)
-yaml
Output as YAML
Variables
Variables are stored in files either as simple key=value pairs, or YAML pairs (key: value). Multiple variable files can be specified by repeating the -v (inject directly as plaintext variables), -c (create and map as ConfigMaps), and -s (create and map as Secrets) flags. These flags are not mutually exclusive, meaning you can specify plaintext, ConfigMaps, and Secrets within the same command:
./kenv \
-v fixtures/vars.env \
-c fixtures/configmap.env \
-s fixtures/secrets.yml \
fixtures/deployment.yaml
YAML Format
YAML files must be in the following format (nested data types are not currently supported):
key1: value1
key2: value2
KV Format
A key=value format is also supported, for example:
key1=value1
key2=value2
Injection
Variables are injected into the resource doc specified by the user as either plaintext environment variables, ConfigMaps, or Secrets. When specifying ConfigMaps and/or Secrets, you must also set a -name for the ConfigMap/Secret resource being created.
kenv injects the variables into the PodSpec for the following resources:
DaemonSetDeploymentReplicaSetReplicationController
Conversion and Support for K8S < 1.4
When using ConfigMap and/or Secret resources in Kubernetes version < 1.4, keys must adhere to the following regex:
\.?[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*
As a convenience, you can pass -convert-keys, which will replace underscores with dashes and convert uppercase strings to lower.
Examples
Plaintext K/V Injection
Variables can be injected as plaintext, directly tied to the containers in the resource document by using the -v flag.
Given the variable file below (fixtures/plaintext.env):
ptkey1=ptvalue1
ptkey2=ptvalue2
Running the following command injecting as plaintext would result in:
$ kenv -yaml -v fixtures/plaintext.env fixtures/deployment.yaml
---
apiVersion: extensions/v1beta1
kind: Deployment
... snip ...
spec:
containers:
- env:
- name: ptkey1
value: ptvalue1
- name: pykey2
value: ptvalue2
image: nginx:latest
... snip ...
ConfigMap Injection
Variables can be injected as ConfigMaps references by specifying variable files with the flag -c. This will both print a ConfigMap resource to be created and modify the specified resource to use the ConfigMap.
Given the variable file below (fixtures/configmap.env):
cmkey1=cmvalue1
cmkey2=cmvalue2
Running the following command injecting as a ConfigMap would result in:
$ kenv -yaml -name nginx -c fixtures/plaintext.env fixtures/deployment.yaml
---
apiVersion: v1
data:
cmkey1: cmvalue1
cmkey2: cmvalue2
kind: ConfigMap
metadata:
name: nginx
namespace: default
---
apiVersion: extensions/v1beta1
kind: Deployment
... snip ...
spec:
containers:
- env:
- name: cmkey1
valueFrom:
configMapKeyRef:
key: cmkey1
name: nginx
- name: cmkey2
valueFrom:
configMapKeyRef:
key: cmkey2
name: nginx
image: nginx:latest
... snip ...
Secret Injection
Variables can be injected as Secret references by specifying variable files with the flag -s. This will both print a Secret resource to be created and modify the specified resource to use the Secret.
Given the variable file below (fixtures/secrets.yml):
secretkey1: secretvalue1
secretkey2: secretvalue2
Running the following command injecting as a ConfigMap would result in:
$ kenv -yaml -name nginx -s fixtures/secrets.yml fixtures/deployment.yaml
---
apiVersion: v1
data:
secretkey1: YzJWamNtVjBkbUZzZFdVeA==
secretkey2: YzJWamNtVjBkbUZzZFdVeQ==
kind: Secret
metadata:
creationTimestamp: null
name: nginx
namespace: default
---
apiVersion: extensions/v1beta1
kind: Deployment
... snip ...
spec:
containers:
- env:
- name: secretkey1
valueFrom:
secretKeyRef:
key: secretkey1
name: nginx
- name: secretkey2
valueFrom:
secretKeyRef:
key: secretkey2
name: nginx
image: nginx:latest
... snip ...
Plaintext, ConfigMaps, and Secrets
Combining the examples above into one command, you would get the following output:
$ kenv -yaml -name nginx -v fixtures/plaintext.env -c fixtures/configmap.env -s fixtures/secrets.yml fixtures/deployment.yaml
---
apiVersion: v1
data:
secretkey1: YzJWamNtVjBkbUZzZFdVeA==
secretkey2: YzJWamNtVjBkbUZzZFdVeQ==
kind: Secret
metadata:
name: nginx
namespace: default
---
apiVersion: v1
data:
cmkey1: cmvalue1
cmkey2: cmvalue2
kind: ConfigMap
metadata:
name: nginx
namespace: default
---
apiVersion: extensions/v1beta1
kind: Deployment
... snip ...
spec:
containers:
- env:
- name: ptkey1
value: ptvalue1
- name: pykey2
value: ptvalue2
- name: secretkey1
valueFrom:
secretKeyRef:
key: secretkey1
name: nginx
- name: secretkey2
valueFrom:
secretKeyRef:
key: secretkey2
name: nginx
- name: cmkey1
valueFrom:
configMapKeyRef:
key: cmkey1
name: nginx
- name: cmkey2
valueFrom:
configMapKeyRef:
key: cmkey2
name: nginx
image: nginx:latest
... snip ...
Building
govendor sync
go test -v .