Sometimes missing desiredContainers - kubernetes

Question

My Zalenium is deployed in Kubernetes. I have set option desiredContainers = 2 and it's working. But sometimes desired containers are not available. Tests are working properly, even when desired containers not available. After "restart" containers appears, but I have no idea why they sometimes dissapears. Does anyone have idea what's going on?
kind: Deployment
apiVersion: extensions/v1beta1
metadata:
name: zalenium
namespace: zalenium-omdc
selfLink: /apis/extensions/v1beta1/namespaces/zalenium-omdc/deployments/zalenium
uid: cbafe254-3e28-4889-a09e-ccfa500ff628
resourceVersion: '25201258'
generation: 24
creationTimestamp: '2019-09-17T13:24:52Z'
labels:
app: zalenium
instance: zalenium
annotations:
deployment.kubernetes.io/revision: '24'
kubectl.kubernetes.io/last-applied-configuration: >
{"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"labels":{"app":"zalenium","instance":"zalenium"},"name":"zalenium","namespace":"zalenium-omdc"},"spec":{"replicas":1,"selector":{"matchLabels":{"instance":"zalenium"}},"template":{"metadata":{"labels":{"app":"zalenium","instance":"zalenium"}},"spec":{"containers":[{"args":["start"],"env":[{"name":"ZALENIUM_KUBERNETES_CPU_REQUEST","value":"250m"},{"name":"ZALENIUM_KUBERNETES_CPU_LIMIT","value":"1000m"},{"name":"ZALENIUM_KUBERNETES_MEMORY_REQUEST","value":"500Mi"},{"name":"ZALENIUM_KUBERNETES_MEMORY_LIMIT","value":"2Gi"},{"name":"DESIRED_CONTAINERS","value":"2"},{"name":"MAX_DOCKER_SELENIUM_CONTAINERS","value":"16"},{"name":"SELENIUM_IMAGE_NAME","value":"elgalu/selenium"},{"name":"VIDEO_RECORDING_ENABLED","value":"true"},{"name":"SCREEN_WIDTH","value":"1440"},{"name":"SCREEN_HEIGHT","value":"900"},{"name":"MAX_TEST_SESSIONS","value":"1"},{"name":"NEW_SESSION_WAIT_TIMEOUT","value":"1800000"},{"name":"DEBUG_ENABLED","value":"false"},{"name":"SEND_ANONYMOUS_USAGE_INFO","value":"true"},{"name":"TZ","value":"UTC"},{"name":"KEEP_ONLY_FAILED_TESTS","value":"false"},{"name":"RETENTION_PERIOD","value":"3"}],"image":"dosel/zalenium:3","imagePullPolicy":"IfNotPresent","livenessProbe":{"httpGet":{"path":"/status","port":4444},"initialDelaySeconds":90,"periodSeconds":5,"timeoutSeconds":1},"name":"zalenium","ports":[{"containerPort":4444,"protocol":"TCP"}],"readinessProbe":{"httpGet":{"path":"/status","port":4444},"timeoutSeconds":1},"resources":{"requests":{"cpu":"500m","memory":"500Mi"}},"volumeMounts":[{"mountPath":"/home/seluser/videos","name":"zalenium-videos"},{"mountPath":"/tmp/mounted","name":"zalenium-data"}]}],"serviceAccountName":"zalenium","volumes":[{"emptyDir":{},"name":"zalenium-videos"},{"emptyDir":{},"name":"zalenium-data"}]}}}}
spec:
replicas: 1
selector:
matchLabels:
instance: zalenium
template:
metadata:
creationTimestamp: null
labels:
app: zalenium
instance: zalenium
spec:
volumes:
- name: zalenium-videos
emptyDir: {}
- name: zalenium-data
emptyDir: {}
containers:
- name: zalenium
image: 'dosel/zalenium:3'
args:
- start
ports:
- containerPort: 4444
protocol: TCP
env:
- name: ZALENIUM_KUBERNETES_CPU_REQUEST
value: 250m
- name: ZALENIUM_KUBERNETES_CPU_LIMIT
value: 1000m
- name: ZALENIUM_KUBERNETES_MEMORY_REQUEST
value: 500Mi
- name: ZALENIUM_KUBERNETES_MEMORY_LIMIT
value: 2Gi
- name: DESIRED_CONTAINERS
value: '2'
- name: MAX_DOCKER_SELENIUM_CONTAINERS
value: '16'
- name: SELENIUM_IMAGE_NAME
value: elgalu/selenium
- name: VIDEO_RECORDING_ENABLED
value: 'false'
- name: SCREEN_WIDTH
value: '1920'
- name: SCREEN_HEIGHT
value: '1080'
- name: MAX_TEST_SESSIONS
value: '1'
- name: NEW_SESSION_WAIT_TIMEOUT
value: '7200000'
- name: DEBUG_ENABLED
value: 'false'
- name: SEND_ANONYMOUS_USAGE_INFO
value: 'true'
- name: TZ
value: UTC
- name: KEEP_ONLY_FAILED_TESTS
value: 'false'
- name: RETENTION_PERIOD
value: '3'
- name: SEL_BROWSER_TIMEOUT_SECS
value: '7200'
- name: BROWSER_STACK_WAIT_TIMEOUT
value: 120m
resources:
limits:
memory: 1Gi
requests:
cpu: 500m
memory: 500Mi
volumeMounts:
- name: zalenium-videos
mountPath: /home/seluser/videos
- name: zalenium-data
mountPath: /tmp/mounted
livenessProbe:
httpGet:
path: /status
port: 4444
scheme: HTTP
initialDelaySeconds: 90
timeoutSeconds: 1
periodSeconds: 5
successThreshold: 1
failureThreshold: 3
readinessProbe:
httpGet:
path: /status
port: 4444
scheme: HTTP
timeoutSeconds: 1
periodSeconds: 10
successThreshold: 1
failureThreshold: 3
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
imagePullPolicy: IfNotPresent
restartPolicy: Always
terminationGracePeriodSeconds: 30
dnsPolicy: ClusterFirst
nodeSelector:
dedicated: omdc
serviceAccountName: zalenium
serviceAccount: zalenium
securityContext: {}
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: dedicated
operator: In
values:
- omdc
schedulerName: default-scheduler
tolerations:
- key: dedicated
operator: Equal
value: omdc
effect: NoSchedule
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 25%
maxSurge: 25%
revisionHistoryLimit: 10
progressDeadlineSeconds: 600
status:
observedGeneration: 24
replicas: 1
updatedReplicas: 1
readyReplicas: 1
availableReplicas: 1
conditions:
- type: Available
status: 'True'
lastUpdateTime: '2019-10-22T06:57:52Z'
lastTransitionTime: '2019-10-22T06:57:52Z'
reason: MinimumReplicasAvailable
message: Deployment has minimum availability.
- type: Progressing
status: 'True'
lastUpdateTime: '2019-10-31T09:14:01Z'
lastTransitionTime: '2019-09-17T13:24:52Z'
reason: NewReplicaSetAvailable
message: ReplicaSet "zalenium-6df85c7f49" has successfully progressed.