Configure the NTP service - Elastic Container Instance - Alibaba Cloud Documentation Center

This topic describes how to configure the Network Time Protocol (NTP) service for Elastic Container Instance pods. The NTP service synchronizes the time between containers and the NTP server.

Configuration description

When you create an Elastic Container Instance-based pod, you can add the k8s.aliyun.com/eci-ntp-server annotation to specify the address of the NTP server. This way, the time of the containers in the pod is synchronized with the time of the NTP server.

Important

Annotations must be added to the metadata in the configuration file of the pod. For example, when you create a Deployment, you must add annotations in the spec.template.metadata section.
To use features of Elastic Container Instance, you can add annotations only when you create Elastic Container Instance-based pods. If you add or modify annotations when you update pods, these annotations do not take effect.

Configuration example

Create an application that is used to configure the NTP service.

kubectl create -f set-ntp.yaml

The following code provides the content of a sample set-ntp.yaml file:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-ntp
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      name: test-ntp
      labels:
        app: nginx
        alibabacloud.com/eci: "true" 
      annotations:
        k8s.aliyun.com/eci-ntp-server: 100.100.XX.XX  # The IP address of your NTP server.
    spec:
      containers:
      - name: nginx
        image: registry.cn-shanghai.aliyuncs.com/eci_open/centos:7
        ports:
        - containerPort: 80
        command: ["/bin/sh","-c","sleep 3600" ]

Log on to the container and check whether the NTP service works as expected.

Query the information about the pod.

kubectl get pod

The following command output is returned:

NAME                        READY   STATUS    RESTARTS   AGE
test-ntp-599d5ff9f5-9kb56   1/1     Running   0          3m59s

Access the container.

kubectl exec -it test-ntp-599d5ff9f5-9kb56 -- bash

Query the source from which the time of the container is synchronized.

chronyc sources

Note

If chrony is not installed, you can run the yum -y install chrony command to install chrony.

If the IP address of the NTP server is returned, the NTP service works as expected. Sample command output:

210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last                            sample
===============================================================================
^* 100.100.XX.XX                    2           6     377     35       +40us[ +135us] +/-   14ms