System clock is 153 seconds off
list Michael C. Schultheiss
We're getting an alert on one of our systems that the system clock is 153 seconds off yet when we compare the system's time with the Xymon server's time they're functionally identical. Both systems are synched with NTP via chronyd and we're seeing less than 0.00001 seconds difference when we check chrony's status. What can we check to see why Xymon's thinking the system's 2.5 minutes off? -- Michael Schultheiss, RHCSA, RHCE OIT Administration Sr. Unix Systems Engineer Ivy Tech Community College user-4a65965dd360@xymon.invalid
list Ralph Mitchell
The client assembled the client data message by running a bunch of commands and saving the output to a file. The last few lines written are the client's current clock time. That file is then shipped out to the Xymon server. On the server side, the client clock time is compared to the server time to see if it drifted. If, for whatever reason, that client message is delayed, you'll get exactly the effect you're seeing. Once the client clock time is written to the file, it doesn't change, regardless of how long it takes to deliver the message to the server. Ralph Mitchell On Tue, Jun 11, 2019 at 10:58 PM Michael C. Schultheiss <
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user-ff9f92cb96dd@xymon.invalid> wrote:
We're getting an alert on one of our systems that the system clock is 153 seconds off yet when we compare the system's time with the Xymon server's time they're functionally identical. Both systems are synched with NTP via chronyd and we're seeing less than 0.00001 seconds difference when we check chrony's status. What can we check to see why Xymon's thinking the system's 2.5 minutes off? -- Michael Schultheiss, RHCSA, RHCE OIT Administration Sr. Unix Systems Engineer Ivy Tech Community College user-4a65965dd360@xymon.invalid
list Ralph Mitchell
To actually answer the question - look for network congestion, routing issues, bad cabling, etc. You've ruled out actual clock discrepancies, so the time difference is an artifact caused by the client data message taking 153 seconds to be delivered and processed by the Xymon server. Ralph Mitchell On Tue, Jun 11, 2019 at 11:37 PM Ralph Mitchell <user-00a5e44c48c0@xymon.invalid>
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wrote:
The client assembled the client data message by running a bunch of commands and saving the output to a file. The last few lines written are the client's current clock time. That file is then shipped out to the Xymon server. On the server side, the client clock time is compared to the server time to see if it drifted. If, for whatever reason, that client message is delayed, you'll get exactly the effect you're seeing. Once the client clock time is written to the file, it doesn't change, regardless of how long it takes to deliver the message to the server. Ralph Mitchell On Tue, Jun 11, 2019 at 10:58 PM Michael C. Schultheiss < user-ff9f92cb96dd@xymon.invalid> wrote:We're getting an alert on one of our systems that the system clock is 153 seconds off yet when we compare the system's time with the Xymon server's time they're functionally identical. Both systems are synched with NTP via chronyd and we're seeing less than 0.00001 seconds difference when we check chrony's status. What can we check to see why Xymon's thinking the system's 2.5 minutes off? -- Michael Schultheiss, RHCSA, RHCE OIT Administration Sr. Unix Systems Engineer Ivy Tech Community College user-4a65965dd360@xymon.invalid