Container Compute Service:ACS pod overview

ACS pod specification adjustment logic

For example, if the sum of .resources.requests or .resources.limits is 2 vCPUs and 3.5 GiB of memory, ACS automatically adjusts the pod specification to 2 vCPUs and 4 GiB of memory upon startup. The additional resources are applied to the first container, and the pod receives the annotation alibabacloud.com/pod-use-spec=2-4Gi. Example resource declaration:

apiVersion: v1 
kind: Pod
metadata:
  labels:
    app: nginx
    alibabacloud.com/compute-class: general-purpose
    alibabacloud.com/compute-qos: default
  name: nginx
spec:
  containers:
  - name: nginx
    image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: 2 # Request 2 vCPUs.
        memory: "3.5Gi" # Request 3.5 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.

Adjusted resource declaration:

apiVersion: v1 
kind: Pod
metadata:
  annotations:
    alibabacloud.com/pod-use-spec: "2-4Gi"
  labels:
    app: nginx
    alibabacloud.com/compute-class: general-purpose
    alibabacloud.com/compute-qos: default
  name: nginx
spec:
  containers:
  - name: nginx
    image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: 2 # Request 2 vCPUs.
        memory: "4Gi" # Request 4 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.

Specify pod specifications using annotations

Applicable scope

• This feature supports only CPU pods of the general-purpose and performance-enhanced compute classes.

• The maximum specification supported by the annotation is 64 vCPUs and 512 GiB of memory, which is subject to the limits described in General-purpose compute class specifications.

Usage

For scenarios where the pod's Quality of Service (QoS) class is Burstable (.resources.limits > .resources.requests), you can declare the target resource specifications for the pod by specifying the annotation alibabacloud.com/pod-required-spec: "X-YGi". The resource specifications must be in the <CPU>-<Memory> format, where CPU is specified in cores (for example, "2" represents 2 vCPUs) and memory is specified in GiB (for example, "4Gi" represents 4 GiB). The detailed resource adjustment and usage rules are as follows:

1. If the specification format is invalid (for example, it is missing units, uses Mi, or is in the incorrect order), the pod fails to be created.

2. If the annotation is set but no container defines .resources, ACS strictly follows the annotation value and does not fall back to the default specification (for example, 2 vCPUs and 4 GiB of memory).

3. If the annotation value is less than the sum of all containers' .resources.requests, the pod fails to be created.

4. If the annotation value exceeds the sum of all containers' .resources.limits, ACS uses the annotation value as the target specification.

   In multi-container pods, the first container is identified as the primary container. The difference between the annotation value and the sum of the current limits is allocated to the primary container's .resources.limits (and .resources.requests if necessary) so that the pod's total resources match the target specification.

Example

For example, if you set the annotation to alibabacloud.com/pod-required-spec: "2-4Gi" and the sum of the container's .resources.requests or .resources.limits is 1 vCPU and 2 GiB of memory, ACS automatically sets the pod specification to 2 vCPUs and 4 GiB of memory when it launches the pod. The additional resources are applied to the first container, and the pod is annotated with alibabacloud.com/pod-use-spec=2-4Gi.

Example resource declaration:

In this example, .resources.limits.memory is 3.5 GiB.

apiVersion: v1 
kind: Pod
metadata:
  labels:
    app: nginx
    alibabacloud.com/compute-class: general-purpose
    alibabacloud.com/compute-qos: default
  annotations:
    alibabacloud.com/pod-required-spec: "2-4Gi"
  name: nginx
spec:
  containers:
  - name: nginx
    image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: 1 # Request 1 vCPU.
        memory: "2Gi" # Request 2 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.
      limits:
        cpu: 2 # Request 2 vCPUs.
        memory: "3.5Gi" # Request 3.5 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.

Adjusted resource declaration:

In the adjusted declaration, .resources.limits.memory is changed from 3.5 GiB to 4 GiB.

apiVersion: v1 
kind: Pod
metadata:
  annotations:
    alibabacloud.com/pod-required-spec: "2-4Gi"
    alibabacloud.com/pod-use-spec: "2-4Gi"
  labels:
    app: nginx
    alibabacloud.com/compute-class: general-purpose
    alibabacloud.com/compute-qos: default
  name: nginx
spec:
  containers:
  - name: nginx
    image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: 1 # Request 1 vCPU.
        memory: "2Gi" # Request 2 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.
      limits:
        cpu: 2 # Request 2 vCPUs.
        memory: "4Gi" # Request 4 GiB of memory.
        ephemeral-storage: "30Gi" # Request 30 GiB of storage.

Automatic specification adjustment

If you do not specify a specification, GPU container pods use the smallest pod specification based on the GPU type. For example, 2 vCPUs, 2 GiB of memory, and one GPU card.

ACS automatically adjusts unsupported specifications. After the adjustment, the container's .resources.requests remains unchanged, but the pod specification is available in the alibabacloud.com/pod-use-spec annotation. If a container's specified resource limit (resources.limits) exceeds the pod specification, ACS sets the container's resource limit to the pod specification.