Define environment variables¶
Sometimes you need to define new environment variables to provide additional configuration for the components of your cluster. For example, you can use it to customize the configuration of HAProxy, or to add additional options for PMM Client.
The Operator can store environment variables in Kubernetes Secrets. Here is an example with several HAProxy options:
apiVersion: v1
kind: Secret
metadata:
name: my-env-var-secrets
type: Opaque
data:
HA_CONNECTION_TIMEOUT: MTAwMA==
OK_IF_DONOR: MQ==
HA_SERVER_OPTIONS: Y2hlY2sgaW50ZXIgMzAwMDAgcmlzZSAxIGZhbGwgNSB3ZWlnaHQgMQ==
As you can see, environment variables are stored as data - i.e.,
base64-encoded strings, so you’ll need to encode the value of each variable.
For example, To have HA_CONNECTION_TIMEOUT variable equal to 1000, you
can run echo -n "1000" | base64 --wrap=0 (or just echo -n "1000" | base64
in case of Apple macOS) in your local shell and get MTAwMA==.
Note
Similarly, you can read the list of options from a Base64-encoded string:
$ echo "MTAwMA==" | base64 --decode
When ready, apply the YAML file with the following command:
$ kubectl create -f deploy/my-env-secret.yaml
Put the name of this Secret to the envVarsSecret key either in pxc,
haproxy or proxysql section of the deploy/cr.yaml` configuration file:
haproxy:
....
envVarsSecret: my-env-var-secrets
....
Now apply the deploy/cr.yaml file with the following command:
$ kubectl apply -f deploy/cr.yaml
Another example shows how to pass LD_PRELOAD environment variable with the
alternative memory allocator library name to mysqld. It’s often a recommended
practice to try using an alternative allocator library for mysqld in case the
memory usage is suspected to be higher than expected, and you can use jemalloc
allocator already present in Percona XtraDB Cluster Pods with the following
environment variable:
LD_PRELOAD=/usr/lib64/libjemalloc.so.1
Create a new YAML file with the contents similar to the previous example, but
with LD_PRELOAD variable, stored as base64-encoded strings:
apiVersion: v1
kind: Secret
metadata:
name: my-new-env-var-secrets
type: Opaque
data:
LD_PRELOAD: L3Vzci9saWI2NC9saWJqZW1hbGxvYy5zby4x
If this YAML file was named deploy/my-new-env-var-secret, the command
to apply it will be the following one:
$ kubectl create -f deploy/my-new-env-secret.yaml
Now put the name of this new Secret to the envVarsSecret key in pxc
section of the deploy/cr.yaml` configuration file:
pxc:
....
envVarsSecret: my-new-env-var-secrets
....
Don’t forget to apply the deploy/cr.yaml file, as usual:
$ kubectl apply -f deploy/cr.yaml
