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FusionInsight HD 6.5.0 Administrator Guide 02

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Replacing the NTP Server for the Cluster

Replacing the NTP Server for the Cluster

Scenario

After the FusionInsight Manager is installed, if no NTP server is configured or the configured NTP server is no longer used, Administrators can replace the NTP server or specify a new NTP server for the cluster to synchronize time with the new NTP clock source.

Impact on the System

  • Replacing the NTP server is a critical operation and may result in time change in the cluster.
  • Before replacing the NTP server, if the time difference between the NTP server and the cluster is greater than 150s, you need to stop the cluster first to prevent data loss. Service interruption occurs when the cluster is stopped.

Prerequisites

A new NTP server is ready, the IP address of the new NTP server is obtained, and the network between the new NTP server and the cluster is configured.

Procedure

  1. Log in to FusionInsight Manager and check whether any alarm is not cleared.

    • If yes, seeTroubleshooting to handle the alarm. After the alarm is handled, go to Step 2.
    • If no, go to Step 2.

  2. Use PuTTY to log in to the active and standby management nodes as user omm.
  3. Run the following command on the active management node to check the management plane gateway:

    cat ${BIGDATA_HOME}/om-server/OMS/workspace/conf/oms-config.ini | grep om_gateway

  4. Run the ping management plane gateway command on the active and standby management nodes, check whether the nodes are connected to the management plane gateway.

    • If yes, go to Step 5.
    • If no, contact the network administrator to rectify the network fault. After exceptions are handled, go to Step 5.

  5. On the active management node, check the time difference between the new NTP server and the cluster. The unit is second.

    • Red Hat

      For example, to check the time difference with the NTP server 10.1.1.1, run the ntpdate -d 10.1.1.1 command. The following information is displayed:

      31 Jan 10:10:10 ntpdate[6015]: adjust time server 10.1.1.1 offset -0.000020 sec

      In the information, -0.000020 indicates the time difference. If the value is a positive number, the time of the NTP server is faster than the time of the cluster; if the value is a negative number, the time of the NTP server is slower than the time of the cluster

    • SUSE

      For example, to check the time difference with the NTP server 10.1.1.1, run the su - root command and enter the password to switch to user root, and then query the version and then run the sntp 10.1.1.1 command.

      • If the NTP version is 4.2.4p, the following information is displayed after you run the sntp 10.1.1.1 command:
        10.1.1.112:~ # sntp 10.1.1.1
        2016 Feb 02 17:45:59.064 + 427.949528 +/- 0.011 secs

        In the information, +427.949528 indicates the time difference. If the value is a positive number, the time of the NTP server is slower than the time of the cluster; if the value is a negative number, the time of the NTP server is faster than the time of the cluster

      • If the NTP version is 4.2.8p, the following information is displayed after you run the sntp 10.1.1.1 command:
        10.1.1.112:~ # sntp 10.1.1.1
        sntp 4.2.8p8@1.3265-o Mon Jun  6 08:01:59 UTC 2016 (1)
        2017-10-24 09:23:28.182627 (+0800) +427.949528 +/- 285.309908 10.1.1.1 s1 no-leap

        In the information, +427.949528 indicates the time difference. If the value is a positive number, the time of the NTP server is faster than the time of the cluster; if the value is a negative number, the time of the NTP server is slower than the time of the cluster.

        NOTE:

        You can run the ntpq -v or ntpq --version command to query the NTP version.

        • Output of the ntpq -v command:
          10.1.1.112: ~#ntpq -v
          ntpq - standard NTP query program - Ver. 4.2.4p8
        • Output of the ntpq --version command:
          10.1.1.112: ~# ntpq --version
          ntpq 4.2.8p10@1.3728-o Mon Jun  6 08:01:59 UTC 2016 (1)

  6. Check whether the absolute value of the time difference exceeds 150.

  7. Check whether the cluster can be stopped.

    • If yes, stop the upper services and then stop the cluster, and go to Step 8.
    • If no, no further operation is required.

  8. Check whether the time of the NTP server time is slower than the time of the cluster.

    • If yes, after the cluster portal displays Operation succeeded, wait until the time difference obtained in Step 5 is due and perform Step 10 as user omm.
    • If no, after the cluster portal displays Operation succeeded, perform Step 10 as user omm at once.

  9. Run the following command on the active management node to replace the NTP server. No further action is required.

    sh ${BIGDATA_HOME}/om-server/om/bin/tools/modifyntp.sh --ntp_server_ip 10.1.1.1

    NOTE:
    • The IP address of the NTP server cannot be set to the IP address of a node in the cluster. Otherwise, the service network between the node and the active/standby OMS nodes may be disconnected.
    • A maximum of two NTP servers in active/standby mode can be configured. Use a comma (,) to separate the servers for example, sh ${BIGDATA_HOME}/om-server/om/bin/tools/modifyntp.sh --ntp_server_ip 10.1.1.1,10.1.1.2.

  10. Run the following command on the active management node to forcibly synchronize time from the NTP server 10.1.1.1 at once and replace the NTP server. No further action is required.

    sh ${BIGDATA_HOME}/om-server/om/bin/tools/modifyntp.sh --ntp_server_ip 10.1.1.1 --force_sync_time

    NOTE:
    • A maximum of two NTP servers in active/standby mode can be configured. Use a comma (,) to separate the servers for example, sh ${BIGDATA_HOME}/om-server/om/bin/tools/modifyntp.sh --ntp_server_ip 10.1.1.1,10.1.1.2 --force_sync_time.
    • If the cluster is stopped, start the cluster after the NTP server is replaced.
    • After the command for forcible time synchronization is executed, it takes about five minutes for time synchronization of cluster nodes.

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Updated: 2019-05-17

Document ID: EDOC1100074522

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