Kubernetes: ConfigMaps and Secrets on a Gorush server example
We have a Gorush server from the Kubernetes: running a push-server with Gorush behind an AWS LoadBalancer post, and I’d like to add an ability to configure it via a Github repository and run it with a different set of settings — for Staging and Production environments.
Let’s use Kubernetes ConfigMap to store a config-file content, and Kubernetes Secrets — for confidential data.
At this moment in the gorush-configmap.yaml
we have default configMap for the Gorush with Redis connection settings:
apiVersion: v1
kind: ConfigMap
metadata:
name: gorush-config
namespace: gorush
data:
# stat
stat.engine: redis
stat.redis.host: redis:6379
Also, need to add:
- an SSL certificate used for Apple Push service authentification
- a password for this certificate
We will add two secrets — one for the password, and one for the key-file.
Kubernetes Secrets
Create a new file gorush-secrets.yaml
and add a p12-key body.
As this is p12 — use the data
type for the secret, get your certificate in the base64
:
$ cat apns_wl.p12 | base64
MIIM9QIBAzCCDLwGCSqGSIb3DQEHAaCCDK0EggypMIIMpTCCBycGCSqGSIb3DQEHBqCCBxgwggcU
AgEAMIIHDQYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQI+BcNML0eE1oCAggAgIIG4KVvRBPp
…
Add a data
map named ios-push-rsa-key:
---
apiVersion: v1
kind: Secret
metadata:
name: ios-push-secret
namespace: gorush
type: Opaque
data:
ios-push-rsa-key: |
MIIM9QIBAzCCDLwGCSqGSIb3DQEHAaCCDK0EggypMIIMpTCCBycGCSqGSIb3DQEHBqCCBxgwggcU
AgEAMIIHDQYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQI+BcNML0eE1oCAggAgIIG4KVvRBPp
...
Or. if it is a PEM-encoded key — you can use stringData
without base64
, just a plaintext:
---
apiVersion: v1
kind: Secret
metadata:
name: ios-push-secret
namespace: gorush
type: Opaque
stringData:
ios-push-rsa-key: |
-----BEGIN CERTIFICATE-----
MIIGJDCCBQygAwIBAgIIAtw7YRUahfYwDQYJKoZIhvcNAQELBQAwgZYxCzAJBgNV
BAYTAlVTMRMwEQYDVQQKDApBcHBsZSBJbmMuMSwwKgYDVQQLDCNBcHBsZSBXb3Js
ZHdpZGUgRGV2ZWxvcGVyIFJlbGF0aW9uczFEMEIGA1UEAww7QXBwbGUgV29ybGR3
...
Create the secret:
$ kubectl apply -f gorush-secrets.yaml
secret/ios-push-secret created
Check it:
$ kubectl -n gorush describe secret ios-push-secret
Name: ios-push-secret
Namespace: gorush
Labels: <none>
Annotations:
Type: Opaque
Data
====
ios-push-rsa-key: 4586 bytes
Now, we need to mount this certificate to pods and containers.
Kubernetes Secrets and volumeMounts
- secrets, as files
Update the gorush-deployment.yaml
file - add volumes
from the sectret:
...
volumes:
- name: ios-push-secret-vol
secret:
secretName: ios-push-secret
items:
- key: ios-push-p12-key
path: apns-crt.p12
And add it to the pod’s template:
...
spec:
containers:
- image: appleboy/gorush
name: gorush
imagePullPolicy: Always
ports:
- containerPort: 8088
...
volumeMounts:
- name: ios-push-secret-vol
mountPath: /data/ssl/apns-crt.p12
subPath: apns-crt.p12
readOnly: true
To make it clear — how they all are tied to each other:
kind: Secret
: // just a Secret typename: ios-push-secret
// a secret name - will use in the spec > volumes > secret > secretNamedata
:ios-push-rsa-key
// a cert bodyvolumes
: // set in the spec, will add volumesname: ios-push-secret-vol
// a created volume name, will be used in the spec > containers >volumeMounts > namesecret
: // defining a data to be usedsecretName: ios-push-secret
// lookup a secret with the name: ios-push-secret nameitems
: // andinsideofthesecret- key: ios-push-rsa-key
// look for the Secrets > data > ios-push-rsa-keypath: apns-rsa.pem
// and how it wmust be mountedvolumeMounts
: // used in the spec > containersname: ios-push-secret-vol
// a volume name to mount - spec > volumes > name: ios-push-secret-volmountPath: /data/ssl/apns-rsa.pem
// a full mount pathsubPath: apns-rsa.pem
// a file name in a directory if a Secret is mounted as a dedicated file
Deploy and check:
kubectl -n gorush exec -ti gorush-7ff8fd9f4c-gds8r -c bastion cat /data/ssl/apns-rsa.pem
Bag Attributes
friendlyName: Apple Push Services: ***
localKeyID: C0 3A 96 69 CB C4 9E E6 14 EB 43 1F 31 30 97 4D 85 89 A0 8D
subject=/UID=***/CN=Apple Push Services: ***/OU=7MF8BB6LXN/O=***/C=VG
issuer=/C=US/O=Apple Inc./OU=Apple Worldwide Developer Relations/CN=Apple Worldwide Developer Relations Certification Authorit
— — -BEGIN CERTIFICATE — — -
MIIGJDCCBQygAwIBAgIIAtw7YRUahfYwDQYJKoZIhvcNAQELBQAwgZYxCzAJBgNV
BAYTAlVTMRMwEQYDVQQKDApBcHBsZSBJbmMuMSwwKgYDVQQLDCNBcHBsZSBXb3Js
…
Kubernetes Secrets and env
- secrets, as environment variables
The following step is to add a password for this certificate.
There are two options — using a config file, or via variables.
In the config file, Gorush has an ios.password
parameter:
...
ios:
enabled: true
key_path: "/data/ssl/apns-crt.p12"
password: "p@ssw0rd"
production: true
...
And if using a variable — Gorush will add a GORUSH
prefix:
...
viper.SetEnvPrefix("gorush") // will be uppercased automatically
...
So, our variable name will be GORUSH_IOS_PASSWORD
.
Add new values to the ios-push-secret.
Add an additional map with the stringData
type:
---
apiVersion: v1
kind: Secret
metadata:
name: ios-push-secret
namespace: gorush-stage
type: Opaque
data:
ios-push-p12-key: |
MIIM9QIBAzCCDLwGCSqGSIb3DQEHAaCCDK0EggypMIIMpTCCBycGCSqGSIb3DQEHBqCCBxgwggcU
AgEAMIIHDQYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQI+BcNML0eE1oCAggAgIIG4KVvRBPp
...
stringData:
ios-push-p12-pass: p@ssw0rd
Check it:
$ kubectl apply -f gorush-secrets.yaml
secret/ios-push-secret configured
And check now — there must be two objects in the secret — view them using describe secret
:
$ kubectl -n gorush describe secret ios-push-secret
Name: ios-push-secret
Namespace: gorush
Labels: <none>
Annotations:
Type: Opaque
Data
====
ios-push-p12-key: 3321 bytes
ios-push-p12-pass: 13 bytes
Add the GORUSH_IOS_PASSWORD
variable to the deployment using secretKeyRef
:
...
spec:
containers:
- image: appleboy/gorush
name: gorush
imagePullPolicy: Always
ports:
- containerPort: 8088
...
env:
- name: GORUSH_IOS_PASSWORD
valueFrom:
secretKeyRef:
name: ios-push-secret
key: ios-push-p12-pass
volumeMounts:
- name: ios-push-secret-vol
mountPath: /data/ssl/apns-crt.p12
subPath: apns-crt.p12
readOnly: true
...
Deploy and check:
$ kubectl -n gorush exec -ti gorush-58bcd746c4–67b9n -c gorush env | grep GORUSH_IOS
GORUSH_IOS_PASSWORD=p@ssw0rd
It’s here.
ConfigMap
Kubernetes ConfigMap — configs, as files
The last thing to do is to add a dedicated config-file for the Gorush itself.
The file will be the same for the Production and Staging, but keys will be passed from a varicose Secrets.
In the same way, using variables and a ConfigMap we can pass any other parameters for different environments.
So, let use a ConfigMap to keep the config.yml
file's content to map it later to pods.
Gorush already has a gorush-configmap.yaml
file - add a new config called gorush-config-file:
---
apiVersion: v1
kind: ConfigMap
metadata:
name: gorush-config
namespace: gorush
data:
# stat
stat.engine: redis
stat.redis.host: redis:6379
---
apiVersion: v1
kind: ConfigMap
metadata:
name: gorush-config-file
namespace: gorush
data:
gorush-config-file: |
core:
enabled: true
mode: "release"
port: "8088"
max_notification: 1000
sync: false
...
Add it to the volumes
in our deployment:
...
volumes:
- name: ios-push-secret-vol
secret:
secretName: ios-push-secret
items:
- key: ios-push-p12-key
path: apns-crt.p12
- name: gorush-config-file-vol
configMap:
name: gorush-config-file
items:
- key: gorush-config-file
path: config.yml
And the on the volumeMounts
in the pods template:
...
spec:
containers:
- image: appleboy/gorush
name: gorush
imagePullPolicy: Always
ports:
- containerPort: 8088
...
env:
- name: GORUSH_IOS_PASSWORD
valueFrom:
secretKeyRef:
name: ios-push-secret
key: ios-push-p12-pass
volumeMounts:
- name: ios-push-secret-vol
mountPath: /data/ssl/apns-crt.p12
subPath: apns-crt.p12
readOnly: true
- name: gorush-config-file-vol
mountPath: /config.yml
readOnly: true
subPath: config.yml
...
Update configmaps:
$ kubectl apply -f gorush-configmap.yaml
configmap/gorush-config unchanged
configmap/gorush-config-file created
Check them:
$ kubectl -n gorush get configmap
NAME DATA AGE
gorush-config 2 28h
gorush-config-file 1 76s
Apply the deployment and check config in a pod:
$ kubectl -n gorush-stage exec -ti gorush-6bc78df55d-9w9m8 -c gorush cat /config.yml
core:
enabled: true
mode: “release”
port: “8088”
max_notification: 1000
sync: false
…
ios:
enabled: true
key_path: “/data/ssl/apns-crt.p12”
password: “”
production: true
To auto-apply new values from ConfigMaps or Secrets — you can use the Reloader controller, see the Kubernetes: ConfigMap and Secrets — data auto-reload in pods post.
Done.
Originally published at RTFM: Linux, DevOps и системное администрирование.