Change NTP settings of vCloud Director Appliance

What's New in vCloud Director 9.5 – Tom Fojta's Blog

Please find the steps for modifying NTP settings of vCloud Director Appliance.

Change NTP Servers

  1. SSH to vCloud Director appliance as root.
  2. Configure the NTP source for the virtual appliance.
    1. Open the /etc/systemd/timesyncd.conf file to edit, such as vi.
    2. Remove the comment for the NTP configuration, add the NTP settings, and save the changes. Please note that you’ve to leave a space between NTP server FQDNs.  NTP=<FQDN of NTP Server1> <FQDN of NTP Server>

For example, 

Verify the status

  1. Enable the systemd-timesyncd service and verify the status.
    1. Run the timedatectl set-ntp true command to enable the network time synchronization.
    2. Run the systemctl restart systemd-timesyncd to enable the NTP synchronization
    3. Run the timedatectl status and systemctl status systemd-timesyncd.service to verify the status of the service.

Change Time Zone

After you deploy successfully the vCloud Director appliance, you can change the system time zone of the appliance. All vCloud Director appliance instances in the server group must use the same settings.

Please find the steps to change the timezone of vCD appliances here.

vCD : Change SSH Session Idle timeout of vCloud Director Appliance.

Its bit annoying that the SSH connection to vCloud DIrector Appliance get cut off for just idling for a short time. So we may want to tweak the ssh configuration of vCD appliance to keep the connection alive for longer period.
The following two properties of SSHD define how long the SSH session should stay though there is no input received from the client.

ClientAliveCountMax
ClientAliveInterval


Please click here fore more details.

ClientAliveCountMax
Sets the number of client alive messages which may be sent without sshd(8) receiving any messages back from the client. If this threshold is reached while client alive messages are being sent, sshd will disconnect the client, terminating the session. It is important to note that the use of client alive messages is very different from TCPKeepAlive. The client alive messages are sent through the encrypted channel and therefore will not be spoofable. The TCP keepalive option enabled by TCPKeepAlive is spoofable. The client alive mechanism is valuable when the client or server depend on knowing when a connection has become inactive.
The default value is
3.

If ClientAliveInterval is set to 15, and ClientAliveCountMax is left at the default, unresponsive SSH clients will be disconnected after approximately 45 seconds.

ClientAliveInterval
Sets a timeout interval in seconds after which if no data has been received from the client, sshd(8) will send a message through the encrypted channel to request a response from the client. The default is 0, indicating that these messages will not be sent to the client.

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