Elastic Container Instance:Configure the NTP service

Prerequisites

Before you begin, ensure that you have:

• A Kubernetes cluster with the ECI add-on installed

• kubectl configured to connect to your cluster

• The IP address of your NTP server

Usage notes

• Add annotations to the pod metadata section of your configuration file. For a Deployment, this is spec.template.metadata.annotations.

• Annotations take effect only when the pod is created. Adding or modifying the annotation on an existing pod has no effect.

Configure NTP for a pod

1. Create a Deployment manifest. Set the k8s.aliyun.com/eci-ntp-server annotation to your NTP server's IP address.

   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  # Replace with your NTP server IP address.
       spec:
         containers:
         - name: nginx
           image: registry.cn-shanghai.aliyuncs.com/eci_open/centos:7
           ports:
           - containerPort: 80
           command: ["/bin/sh","-c","sleep 3600"]

2. Apply the manifest.

   kubectl create -f set-ntp.yaml

Verify NTP synchronization

1. Get the pod name.

   kubectl get pod

   Expected output:

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

2. Open a shell in the container.

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

3. Check whether chrony is installed. If it is not, install it before proceeding.

   yum -y install chrony

4. Check the NTP time source.

   chronyc sources

   Expected 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

   The ^* in the first column marks the currently active time source. If your NTP server IP address appears on this line, time synchronization is working.