instruction: Create a comprehensive Dockerfile for networking applications with best practices
output: ```dockerfile
  from user accounts, which are authenticated
  human users in the cluster. By default, user accounts don't exist in the Kubernetes
  API server; instead, the API server treats user identities as opaque
  data. You can authenticate as a user account using multiple methods. Some
  Kubernetes distributions might add custom extension APIs to represent user
  accounts in the API server.Comparison between service accounts and usersDescriptionServiceAccountUser or groupLocationKubernetes API (ServiceAccount object)ExternalAccess controlKubernetes RBAC or other authorization mechanismsKubernetes RBAC or other identity and access management mechanismsIntended useWorkloads, automationPeopleDefault service accountsWhen you create a cluster, Kubernetes automatically creates a ServiceAccount
  object named default for every namespace in your cluster. The default
  service accounts in each namespace get no permissions by default other than the
  default API discovery permissions
  that Kubernetes grants to all authenticated principals if role-based access control (RBAC) is enabled.
  If you delete the default ServiceAccount object in a namespace, the
  control plane
  replaces it with a new one.If you deploy a Pod in a namespace, and you don't
  manually assign a ServiceAccount to the Pod, Kubernetes
  assigns the default ServiceAccount for that namespace to the Pod.Use cases for Kubernetes service accountsAs a general guideline, you can use service accounts to provide identities in
  the following scenarios:Your Pods need to communicate with the Kubernetes API server, for example in
  situations such as the following:Providing read-only access to sensitive information stored in Secrets.Granting cross-namespace access, such as allowing a
  Pod in namespace example to read, list, and watch for Lease objects in
  the kube-node-lease namespace.Your Pods need to communicate with an external service. For example, a
  workload Pod requires an identity for a commercially available cloud API,
  and the commercial provider allows configuring a suitable trust relationship.Authenticating to a private image registry using an imagePullSecret.An external service needs to communicate with the Kubernetes API server. For
  example, authenticating to the cluster as part of a CI/CD pipeline.You use third-party security software in your cluster that relies on the
  ServiceAccount identity of different Pods to group those Pods into different
  contexts.How to use service accountsTo use a Kubernetes service account, you do the following:Create a ServiceAccount object using a Kubernetes
  client like kubectl or a manifest that defines the object.Grant permissions to the ServiceAccount object using an authorization
  mechanism such as
  RBAC.Assign the ServiceAccount object to Pods during Pod creation.If you're using the identity
  ```