How to specify specific generations of ECS instance families to create an elastic container instance? - Elastic Container Instance

If you create a pod by specifying the number of vCPUs and memory size, you may have specific requirements for Elastic Compute Service (ECS) instance types. For example, you want to use an instance type of only sixth-generation ECS instance families, such as g6 or c6, to create the pod. In this case, you can add the k8s.aliyun.com/eci-instance-generation annotation to specify the generations of ECS instance families. This topic describes how to specify or exclude specific generations of ECS instance families when you create a pod.

Feature description

When you create an Elastic Container Instance pod by specifying the number of vCPUs and memory size, the system uses a variety of ECS instance types to support the creation and automatically selects the instance types that meet the vCPUs and memory requirements and have sufficient resources. In this case, you can add the k8s.aliyun.com/eci-instance-generation annotation to specify or exclude specific generations of ECS instance families.

If you specify specific generations of ECS instance families, the system selects ECS instance types only from the specified generations of ECS instance families. If the resources of the specified generations of ECS instance families are insufficient, the system does not create a pod.
If you exclude specific generations of ECS instance families, the system selects ECS instance types from other generations of ECS instance families that are supported by Elastic Container Instance to create a pod.

The following table describes the generations of ECS instance families that you can specify or exclude when you create pods. The following table also describes the ECS instance families of the generations.

Architecture	Generation of ECS instance families	ECS instance family
ARM	8	g8y, c8y, and r8y
x86	7	g7, c7, r7, hfc7, hfg7, hfr7, and g7ne
	6	g6e, g6, c6e, c6, r6e, r6, hfc6, hfg6, and t6
	5	u1, g5,g5ne, c5, r5, ic5, hfc5, hfg5, and t5
	4	sn2ne, sn1ne, se1ne, and se1

For more information about ECS instance types, see the following topics:

Precautions

Pods that are created based on specific generations of ECS instance families are billed based on the actually used ECS instance type. The pods are not billed based on the specified number of vCPUs and memory size.
Important
After a pod is created, you can run the kubectl describe pod command to view the YAML details of the pod. The value of the k8s.aliyun.com/eci-instance-spec field indicates the ECS instance type that is used by the pod. The pod is billed based on the ECS instance type.
When you specify or exclude specific generations of ECS instance families, the system cannot automatically select specific instance types. For example, the system cannot automatically select GPU-accelerated instance types, such as the instance types of the gn6i instance family, and instance types equipped with local disks, such as instance types of the i2g instance family. If you want to use specific ECS instance types, create pods by specifying ECS instance types. For more information, see Specify ECS instance types to create a pod.
You can specify or exclude specific generations of ECS instance families to create preemptible elastic container instances. In this scenario, the system selects the most suitable ECS instance type based on the market price and the sequence of the generations of ECS instance families that you configured. If you have strict requirements for the generations of ECS instance families, we recommend that you specify only one generation.
The feature of specifying or excluding specific generations of ECS instance families takes effect only when you create pods by specifying the number of vCPUs and memory size. If you first specify ECS instance types when you create pods, the feature does not take effect.
The feature of specifying or excluding specific generations of ECS instance families cannot be used to create job-optimized elastic container instances. The feature cannot be used together with the k8s.aliyun.com/eci-network-config annotation.

Configuration description

Valid values of k8s.aliyun.com/eci-instance-generation are generations of ECS instance families. Take note of the following items:

You can configure multiple generations. Valid values are the generations of the ECS instance families that can be used to create pods.
Important
The 8th-generation ECS instance families support only the ARM architecture. When you specify 8th-generation ECS instance families to create a pod, you must set the nodeSelector field to schedule the pod to an ARM-based virtual node. Therefore, you cannot specify 8th-generation ECS instance families together with the ECS instance families that use the x86 architecture. When you create ARM-based pods, you do not need to specify or exclude specific generations of ECS instance families. It is redundant to separately specify or exclude the 8th-generation ECS instance families. For more information, see Schedule pods to an ARM-based virtual node and ECS instance types of the ARM architecture.
If you add a minus sign (-) before a generation of ECS instance families, the generation is excluded.
For example, k8s.aliyun.com/eci-instance-generation: "-5,-4" specifies that fifth- and fourth-generation ECS instance families are excluded and seventh- or six-generation ECS instance families are used.
The system selects the specified generations based on the order in which they are specified.
For example, the k8s.aliyun.com/eci-instance-generation: "6,5" annotation specifies that the system preferentially uses sixth-generation ECS instance families. If the resources of sixth-generation ECS instance families that meet the required vCPU and memory specifications are insufficient, fifth-generation ECS instance families are used. If the resources of fifth-generation ECS instance families are also insufficient, no pod is created.

Before you use the k8s.aliyun.com/eci-instance-generation annotation, you must specify the number of vCPUs and memory size by using one of the following methods:

Specify the limits or requests parameter of containers. We recommend that you specify the limits parameter.
Add the k8s.aliyun.com/eci-use-specs annotation to the metadata of the pod.

Example 1: Specify specific generations of ECS instance families

Configuration item	Effect
The limits parameter is configured to define vCPU and memory resources (2 vCPUs, 4 GiB of memory). The `k8s.aliyun.com/eci-instance-generation: "6,5"` annotation is configured. The annotation specifies that the system first uses sixth-generation ECS instance families and then fifth-generation ECS instance families.	The system preferentially selects instance types from sixth-generation ECS instance families that meet the required vCPU and memory specifications. If the resources of sixth-generation ECS instance families are insufficient, the system selects instance types from fifth-generation ECS instance families.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-instance-generation: "6,5"    # Specifies that the sixth-generation ECS instance families and fifth-generation ECS instance families are used in sequence.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80
        resources:
          limits:
            cpu: "2"       # Specifies the maximum number of vCPUs.        
            memory: "4Gi"  # Specifies the maximum memory size.

Example 2: Exclude specific generations of ECS instance families

Configuration item	Effect
The `k8s.aliyun.com/eci-use-specs: "2-4Gi"` annotation is configured to define vCPU and memory resources (2 vCPUs, 4 GiB of memory). The `k8s.aliyun.com/eci-instance-generation: "-5,-4"` annotation is configured to exclude fifth- and fourth-generation ECS instance families.	The system selects instance types from seventh- and sixth-generation ECS instance families that meet the required vCPU and memory specifications.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"                    # Specifies vCPU and memory specifications.
        k8s.aliyun.com/eci-instance-generation: "-5,-4"          # Excludes fifth- and fourth-generation ECS instance families.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80

Example 3: Specify specific generations of ECS instance families and exclude specific ECS instance families

Configuration item

Effect

The k8s.aliyun.com/eci-use-specs: "2-4Gi" annotation is configured to define vCPU and memory resources (2 vCPUs, 4 GiB of memory).
The k8s.aliyun.com/eci-instance-generation: "6,5" annotation is configured. The annotation specifies that the system first uses sixth-generation ECS instance families and then fifth-generation ECS instance families.
The k8s.aliyun.com/eci-instance-family: "-ecs.t5" annotation is configured to exclude the ecs.t5 instance family.

The system preferentially selects instance types from sixth-generation ECS instance families that meet the required vCPU and memory specifications.
If the resources of sixth-generation ECS instance families are insufficient, the system selects instance types from fifth-generation ECS instance families (except ecs.t5) that are supported by Elastic Container Instance.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"                   # Specifies vCPU and memory specifications.
        k8s.aliyun.com/eci-instance-generation: "6,5"           # Specifies that the sixth-generation ECS instance families and fifth-generation ECS instance families are used in sequence.
        k8s.aliyun.com/eci-instance-family: "-ecs.t5"           # Excludes the ecs.t5 instance family.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80

Example 4: Exclude specific generations of ECS instance families and specific ECS instance families

Configuration item	Effect
The `k8s.aliyun.com/eci-use-specs: "2-4Gi"` annotation is configured to define vCPU and memory resources (2 vCPUs, 4 GiB of memory). The `k8s.aliyun.com/eci-instance-generation: "-5,-4"` annotation is configured to exclude fifth- and fourth-generation ECS instance families. The `k8s.aliyun.com/eci-instance-family: "-ecs.t6"` annotation is configured to exclude the ecs.t6 instance family.	The system selects instance types from seventh- and sixth-generation ECS instance families (except ecs.t6) that meet the required vCPU and memory specifications.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"                    # Specifies vCPU and memory specifications.
        k8s.aliyun.com/eci-instance-generation: "-5,-4"          # Excludes fifth- and fourth-generation ECS instance families.
        k8s.aliyun.com/eci-instance-family: "-ecs.t6"            # Excludes the ecs.t6 instance family.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80

Example 5: Invalid setting

The feature of specifying or excluding specific generations of ECS instance families takes effect only when you create pods by specifying the number of vCPUs and memory size. If you create pods by specifying ECS instance types, the feature does not take effect. If specified generations of ECS instance families do not take effect, an IgnoreInstanceTypeFeatures event is generated.

Event Name	Type	Event message	Description
IgnoreInstanceTypeFeatures	Warning	[ecs.instance]Ignore instance type features because specific k8s.aliyun.com/eci-use-specs is set	The `k8s.aliyun.com/eci-use-specs` annotation explicitly specifies ECS instance types. The annotation that specifies the generations of ECS instance families is automatically ignored.

In the following example, the annotation that specifies sixth-generation ECS instance families is automatically ignored, and only the ecs.c5.large instance type is used to create a pod:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: nginx-test
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-use-specs: "ecs.c5.large"   # Specifies a specific ECS instance type.
        k8s.aliyun.com/eci-instance-generation: "6"    # Specifies specific generations of ECS instance families. The setting does not take effect.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/nginx:1.14.2
        ports:
        - containerPort: 80