A Deployment controller provides declarative updates for Pods and ReplicaSets. You describe a desired state in a Deployment object, and the Deployment controller changes the actual state to the desired state at a controlled rate.
This document only describes the parameters or field meanings that may be used in creating a deployment, for deployment management please refer to Workload Management. At the same time, Quick Start - Deploy a WordPress Web Application can also help you quickly understand Deployment.
Sign in with project-regular, enter into one project (e.g. demo-namespace), then select Workload → Deployments.
1.1. Click Create Deployment button, then fill in the basic information in the pop-up window. There are two ways to create a deployment, i.e. fill in the creation table and edit mode. The following mainly introduces each step within creation table. If you prefer edit mode, you can click on the edit mode, it supports the yaml and json formats. Edit mode makes it easy for users who are used to command operations.
1.2. On the basic information page, enter the name of the deployment, you can also fill in the description as required.
Click Next when you're done.
2.1. On the Pod Template page, user can set the number of replicas and HPA, HPA is able to automatically scale deployments and increase the overall resource utilization of the cluster.
Note: This guide Setting HPA for Deploymets provides an example of HPA and demonstrates how HPA works.
Click Add Container to add a container image as needed. The image defined in the template is pulled from the DockerHub by default. Enter the name of the container and the corresponding image name. The image name generally needs to be specified with its tag, such as
In order to realize the effective scheduling and allocation of resources in the cluster and improve resources utilization, the platform uses requests and limits to allocate resources. Request is usually the minimum resource requirement used by the container, and limit is usually the maximum value of the resource. Setting it to 0 means that there is no restriction on the resources used. Request can ensure that the pod has enough resources to run, and limit is to prevent a Pod from using resources unrestricted，causing other Pods to crash.
Table 1: CPU Quota Description
|A request is the amount of that CPU resources that the system will guarantee for the container, and Kubernetes will use this value to decide on which node to place the pod.
|A limit is the maximum amount of CPU resources that Kubernetes will allow the container to use.
Table 2: Memory Quota Description
|A request is the amount of that memory resources that the system will guarantee for the container, and Kubernetes will use this value to decide on which node to place the pod.
|A limit is the maximum amount of memory resources that Kubernetes will allow the container to use. If the memory usage exceeds this limit, the container may be killed.
2.2. If the user has further requirements, click on Advanced Options.
Environment Variables: you can define an argument for a Pod using any of the techniques available for defining environment variables, including ConfigMaps and Secrets, which has the same effect as the "ENV" in the Dockerfile, providing great flexibility for creating workloads.
Click Save when setup is complete.
Update policies include RollingUpdate and Recreate:
RollingUpdates: It is recommended to update the deployment using Rolling-update. Rolling upgrade will be used gradually when the new version of the Pod replaces the old version. During rolling upgrade process, the traffic is distributed to the old and new Pods at the same time, so the service is not interrupted. You can specify following two fields to control the rolling update process. - The minimum available number of Pods: Optional, the number of minimum Pods available for each RollingUpdate, is recommended to be a positive integer. - The maximum available number of Pods: Optional, the maximum number of Pods allowed during a rolling upgrade.
Recreate: All existing Pods will be killed before the new Pod is created, meaning that this strategy will delete the old Pod first, then create a new Pod, and the business will be interrupted during the upgrade process.
After completing the above configuration information, click Next.
Deployment suppots totally 3 kind of volumes, i.e. Persistent Storage Volume, Temporary Storage Volume (EmptyDir) and Reference Configuration Center.
Persistent storage volumes can be used to save user's persist data, Add Existing Volume means you need to create volumes in advance, see Create Persistent Storage Volume.
The temporary storage volume represents emptyDir, which is first created when a Pod is assigned to a Node, and exists as long as that Pod is running on that node. When a Pod is removed from a node for any reason, the data in the emptyDir is deleted forever.
It also supports for configuring the key-value pairs in ConfigMap or Secret via reference configuration center.
A secret volume is used to pass sensitive information, such as passwords, to Pods. Secret volumes are backed by tmpfs (a RAM-backed filesystem) so they are never written to non-volatile storage.
ConfigMap is used to store configuration data in the form of key-value pairs. The configMap resource provides a way to inject configuration data into Pods. The data stored in a ConfigMap object can be referenced in a volume of type configMap and then consumed by containerized applications running in a Pod.
Click on the Next button when you're done.
Labels are key/value pairs that are attached to objects, such as pods. Labels are intended to be used to specify identifying attributes of objects that are meaningful and relevant to users. Labels can be used to organize and to select subsets of objects, each object can have a set of key/value labels defined, such as
relase: stable ; tier: frontend.
Click on the Next button when you're done.
For the pod to be eligible to run on a node, the node must have each of the indicated key-value pairs as labels (it can have additional labels as well). The user can specify the node on which the Pod is expected to run by setting one or more sets of key-value pairs or select node directly. When not specified, the Pod will likely be scheduled to any node in the cluster that meets the resource scheduling criteria.
Click Create to complete the creation of the Deployment resource. The status display “Updating” is due to it's pulling the image. After the image pull succeeds, the status will display “Running”.