Elastic Container Instance:Specify the number of vCPUs and memory size to create a pod

Specification description

If the number of vCPUs or memory size that you specify is invalid when you create an elastic container instance, the system adjusts the number or size based on the specifications supported by Elastic Container Instance. When the system adjusts the number or size, the system selects the most similar specifications supported by Elastic Container Instance to create an elastic container instance, and the specifications selected by the system are higher than or equal to the specifications that you specified for the elastic container instance. For example, if you specify 7 vCPUs and 13 GiB of memory to create an elastic container instance, but these specifications are invalid, the system adjusts the number of vCPUs and memory size and selects 8 vCPUs and 16 GiB of memory that are supported by Elastic Container Instance to create an elastic container instance.

The following table describes the specifications supported by Elastic Container Instance.

Configuration description

You can specify the number of vCPUs and memory size to create a pod by using one of the following methods:

• Specify the number of vCPUs and memory size for each container in the pod by using the limits or requests parameter. We recommend that you use the limits parameter.

• Specify the number of vCPUs and memory size for the pod by adding the annotation k8s.aliyun.com/eci-use-specs to the metadata section of the pod.

If you do not specify the limits, requests, or eci-use-specs parameter, or you specify all these parameters, the system creates a pod based on corresponding pod specifications.

Specify the number of vCPUs and memory size for containers in a pod

This method is the default method of creating pods in Kubernetes. You can create a maximum of 20 containers in each pod and configure the vCPU and memory specifications for each container. For each pod, the total vCPU and memory specifications of all containers must be lower than or equal to the vCPU and memory specifications of the pod.

You can specify the number of vCPUs and memory size in the limits parameter for a container. Sample configurations:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80
        resources:
          limits:
            cpu: "500m"      #Specify 0.5 vCPU for the container named nginx.
            memory: "1024Mi"   #Specify 1 GiB of memory for the container named nginx.
      - name: busybox
        image: registry.cn-shanghai.aliyuncs.com/eci_open/busybox:1.30
        command: ["sleep"]
        args: ["999999"]
        resources:
          limits:
            cpu: "1000m"   #Specify 1 vCPU for the container named busybox.
            memory: "2048Mi"  #Specify 2 GiB of memory for the container named busybox.

Specify the number of vCPUs and memory size for a pod

The system provides multiple ECS instance types and selects a suitable one to achieve better elasticity and resource provisioning.

This method provides the following benefits:

• You do not need to specify the number of vCPUs, memory size, or resource limits for containers in the pod. This provides the containers with greater flexibility to share resources.

• In genetic computation and Istio scenarios, the service framework automatically deploys sidecar containers in pods. You can seamlessly connect Elastic Container Instance to the service framework by specifying the number of vCPUs and memory size for a pod.

You can add annotations to the metadata in the configuration file of a pod to specify the number of vCPUs and memory size for the pod. Sample configurations:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-use-specs : "2-4Gi"   # Specify 2 vCPUs and 4 GiB of memory for the pod.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80
      - name: busybox
        image: registry.cn-shanghai.aliyuncs.com/eci_open/busybox:1.30
        command: ["sleep"]
        args: ["999999"]
        resources:
          limits:
            cpu: "500m"     #Specify the maximum number of vCPUs for a container.        
            memory: "1024Mi"   #Specify the maximum memory size for a container.