When the cluster is configured to use an external NTP server for time synchronization, the system periodically checks connectivity to the NTP server and the time synchronization status. If an anomaly is detected, the corresponding alert is triggered.
The cluster failed to connect to the external NTP server.
The cluster is unable to synchronize with the external NTP server.
The host { .labels.hostname } cannot synchronize time with the NTP server.
The host { .labels.hostname } cannot establish a connection with the NTP server.
The time difference between the host { .labels.hostname } and the NTP server is greater than { .threshold }.
The SCVM { .labels.hostname } cannot synchronize time with the NTP server.
The SCVM { .labels.hostname } cannot establish a connection with the NTP server.
The time difference between the SCVM { .labels.hostname } and the NTP server is greater than { .threshold }.
SCVM { .labels.hostname }: The time difference with the cluster has exceeded { .threshold }.
The time difference between the witness node { .labels.hostname } and the NTP server is greater than { .threshold }.
Witness node { .labels.hostname }: The time difference with the cluster has exceeded { .threshold }.
If an NTP configuration anomaly occurs, the clocks on the cluster hosts may deviate from the external time source. This does not affect the normal operation of cluster services, but may affect the display of time-sensitive information such as logs, alerts, and monitoring data.
Common causes include:
The external NTP server clock is abnormal, with an excessively large time difference from the host.
The external NTP server configuration is incorrect, such as a misspelled domain name, incorrect IP address, or failure to configure DNS, preventing domain name resolution.
A network anomaly prevents the host from accessing the NTP server.
Firewall policies on the host or NTP server are blocking the relevant ports.
Investigate each possible cause based on your situation:
Check the configuration
Confirm whether the NTP address is correct. If necessary, update it in the cluster's Settings > Cluster time.
Check the network
Check connectivity between the host and the NTP server, and investigate potential firewall or routing policy issues.
Correct the time offset
If the time difference between the host and the NTP server is too large, manually synchronize the host time to the NTP server. For specific steps, refer to the Adjusting the cluster system time section in ACOS Operations and Maintenance.
