Allow custom Postgres pod environment variables

README.md

@@ -145,6 +145,38 @@ spec:
 Please be aware that the taint and toleration only ensures that no other pod gets scheduled to a PostgreSQL node 
 but not that PostgreSQL pods are placed on such a node. This can be achieved by setting a node affinity rule in the ConfigMap.
 
+#### Custom Pod Environment Variables
+
+It is possible to configure a config map which is used by the Postgres pods as an additional provider for environment variables.
+
+One use case is to customize the Spilo image and configure it with environment variables. The config map with the additional settings is configured in the operator's main config map:
+
+**postgres-operator ConfigMap**
+
+```
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: postgres-operator
+data:
+  # referencing config map with custom settings
+  pod_environment_configmap: postgres-pod-config
+  ...
+```
+
+**referenced ConfigMap `postgres-pod-config`**
+
+```
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: postgres-pod-config
+  namespace: default
+data:
+  MY_CUSTOM_VAR: value
+```
+
+This ConfigMap is then added as a source of environment variables to the Postgres StatefulSet/pods.
 
 # Setup development environment
 

pkg/cluster/k8sres.go

@@ -362,6 +362,13 @@ func (c *Cluster) generatePodTemplate(resourceRequirements *v1.ResourceRequireme
 	if cloneDescription.ClusterName != "" {
 		envVars = append(envVars, c.generateCloneEnvironment(cloneDescription)...)
 	}
+
+	envFromSource := []v1.EnvFromSource{}
+	if c.OpConfig.PodEnvironmentConfigMap != "" {
+		configMapRef := v1.ConfigMapEnvSource{LocalObjectReference: v1.LocalObjectReference{Name: c.OpConfig.PodEnvironmentConfigMap}}
+		envFromSource = append(envFromSource, v1.EnvFromSource{ConfigMapRef: &configMapRef})
+	}
+
 	privilegedMode := true
 	containerImage := c.OpConfig.DockerImage
 	if dockerImage != nil && *dockerImage != "" {
@@ -393,6 +400,7 @@ func (c *Cluster) generatePodTemplate(resourceRequirements *v1.ResourceRequireme
 			},
 		},
 		Env: envVars,
+		EnvFrom: envFromSource,
 		SecurityContext: &v1.SecurityContext{
 			Privileged: &privilegedMode,
 		},

pkg/util/config/config.go

@@ -30,6 +30,7 @@ type Resources struct {
 	DefaultMemoryRequest    string            `name:"default_memory_request" default:"100Mi"`
 	DefaultCPULimit         string            `name:"default_cpu_limit" default:"3"`
 	DefaultMemoryLimit      string            `name:"default_memory_limit" default:"1Gi"`
+	PodEnvironmentConfigMap string            `name:"pod_environment_configmap" default:""`
 	NodeEOLLabel            map[string]string `name:"node_eol_label" default:"lifecycle-status:pending-decommission"`
 	NodeReadinessLabel      map[string]string `name:"node_readiness_label" default:"lifecycle-status:ready"`
 }