Elastic Container Instance:Create a preemptible elastic container instance

Billing

When you create a spot instance, the market price fluctuates based on supply and demand for the instance type. If your bid exceeds the current market price and inventory is sufficient, the instance is created and enters a protection period (default: 1 hour). During the protection period, billing uses the market price at time of purchase. After the protection period, billing switches to the real-time market price.

Spot instances are billed at a lower price than pay-as-you-go instances. For details, see the "Billing methods" section of Preemptible instances.

Reclaim mechanism

After the protection period expires, the system checks the market price and resource inventory every 5 minutes. If the market price exceeds your bid or inventory is insufficient, the instance is released.

A SpotToBeReleased event is generated approximately 3 minutes before release.

After release, billing stops, the ECI instance status changes to Expired, and the pod status changes to Failed with reason BidFailed.

Creation methods

When you specify vCPU count and memory size, the supported combinations are:

If the combination you specify is not supported, the system automatically uses the next supported higher specification.

Example 1: Specify an ECS instance type with a price limit

This example creates a spot instance based on ecs.c6.large with a maximum hourly price of $0.25.

apiVersion: batch/v1
kind: Job
metadata:
  name: test
spec:
  template:
    metadata:
      labels:
        app: perl
        alibabacloud.com/eci: "true"
      annotations:
        k8s.aliyun.com/eci-use-specs: "ecs.c6.large"            # Specify an ECS instance type.
        k8s.aliyun.com/eci-spot-strategy: "SpotWithPriceLimit"  # Use a price cap.
        k8s.aliyun.com/eci-spot-price-limit: "0.25"             # Maximum hourly price.
    spec:
      containers:
      - name: pi
        image: registry.cn-shanghai.aliyuncs.com/eci_open/perl:5
        command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never

Behavior:

• If inventory or the price condition is not met, the instance is not created.

• After creation, the 1-hour protection period begins. After the period expires, the instance is released if the market price exceeds $0.25 or inventory is insufficient.

Example 2: Specify vCPU count and memory size with market-price bidding

Use SpotAsPriceGo to automatically bid at the current market price. Specify the instance size either through pod resource limits or through an annotation.

Option A: Use pod resource limits

apiVersion: batch/v1
kind: Job
metadata:
  name: test
spec:
  template:
    metadata:
      labels:
        app: perl
        alibabacloud.com/eci: "true"
      annotations:
        k8s.aliyun.com/eci-spot-strategy: "SpotAsPriceGo"  # Bid at market price.
    spec:
      containers:
      - name: pi
        image: registry.cn-shanghai.aliyuncs.com/eci_open/perl:5
        command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
        resources:
          limits:
            cpu: 2000m      # 2 vCPUs
            memory: 4096Mi  # 4 GiB
      restartPolicy: Never

Option B: Use the spec annotation

apiVersion: batch/v1
kind: Job
metadata:
  name: test
spec:
  template:
    metadata:
      labels:
        app: perl
        alibabacloud.com/eci: "true"
      annotations:
        k8s.aliyun.com/eci-use-specs: "2-4Gi"              # 2 vCPUs, 4 GiB (minimum 2 vCPUs).
        k8s.aliyun.com/eci-spot-strategy: "SpotAsPriceGo"  # Bid at market price.
    spec:
      containers:
      - name: pi
        image: registry.cn-shanghai.aliyuncs.com/eci_open/perl:5
        command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never

Both options create a 2 vCPU, 4 GiB instance with a 1-hour protection period.

Example 4: Fall back to pay-as-you-go if spot inventory is insufficient

Set eci-spot-fallback to true to automatically create a pay-as-you-go instance when spot inventory is unavailable.

apiVersion: batch/v1
kind: Job
metadata:
  name: test
spec:
  template:
    metadata:
      labels:
        app: perl
        alibabacloud.com/eci: "true"
      annotations:
        k8s.aliyun.com/eci-use-specs: "ecs.c6.large"
        k8s.aliyun.com/eci-spot-strategy: "SpotWithPriceLimit"
        k8s.aliyun.com/eci-spot-price-limit: "0.05"
        k8s.aliyun.com/eci-spot-fallback: "true"           # Fall back to pay-as-you-go.
    spec:
      containers:
      - name: pi
        image: registry.cn-shanghai.aliyuncs.com/eci_open/perl:5
        command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never

Behavior:

• If spot inventory is sufficient: a spot instance is created with a 1-hour protection period.

• If spot inventory is insufficient: a pay-as-you-go instance is created. The system does not auto-release it.

To verify which type was created, run kubectl describe pod and check the Events section. A SpotDegraded event indicates the instance is pay-as-you-go.

Detect an upcoming release

A SpotToBeReleased event is generated approximately 3 minutes before a spot instance is released. Use kubectl describe or kubectl get events to monitor for this event.

# kubectl describe output
Events:
  Type     Reason            Age    From          Message
  ----     ------            ----   ----          -------
  Warning  SpotToBeReleased  3m32s  kubelet, eci  Spot ECI will be released in 3 minutes

# kubectl get events output
LAST SEEN   TYPE      REASON             OBJECT         MESSAGE
3m39s       Warning   SpotToBeReleased   pod/pi-frmr8   Spot ECI will be released in 3 minutes

Check the status after release

After release, billing stops, the ECI instance status changes to Expired, and the pod status changes to Failed with reason BidFailed.

# kubectl get pod output
NAME       READY   STATUS      RESTARTS   AGE
pi-frmr8   1/1     BidFailed   0          3h5m

# kubectl describe output
Status:   Failed
Reason:   BidFailed
Message:  The pod is spot instance, and have been released at 2020-04-08T12:36Z