frontend.Server can only set one Container(main container), should be an array type here

[howieyuen]

k8s api:

InitContainers []Container `json:"initContainers,omitempty" patchStrategy:"merge" patchMergeKey:"name" protobuf:"bytes,20,rep,name=initContainers"`
// List of containers belonging to the pod.
// Containers cannot currently be added or removed.
// There must be at least one container in a Pod.
// Cannot be updated.
// +patchMergeKey=name
// +patchStrategy=merge
Containers []Container `json:"containers" patchStrategy:"merge" patchMergeKey:"name" protobuf:"bytes,2,rep,name=containers"`
// List of ephemeral containers run in this pod. Ephemeral containers may be run in an existing
// pod to perform user-initiated actions such as debugging. This list cannot be specified when
// creating a pod, and it cannot be modified by updating the pod spec. In order to add an
// ephemeral container to an existing pod, use the pod's ephemeralcontainers subresource.
// +optional
// +patchMergeKey=name
// +patchStrategy=merge
EphemeralContainers []EphemeralContainer `json:"ephemeralContainers,omitempty" patchStrategy:"merge" patchMergeKey:"name" protobuf:"bytes,34,rep,name=ephemeralContainers"`