Skip to main content

Network timeouts for VM guests

This is SO weird. That SQL timeout issue was caused by network timeouts, and it disappeared when we moved the SQL server to another ESX host. However, the issue re-appeared, this time on the host with the vCenter guests...

Further analysis reveals this interesting tidbit:

29/06/2009 12:08:29 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 12:08:34 PM -- Request timed out.
...
29/06/2009 12:09:24 PM -- Request timed out.
29/06/2009 12:09:26 PM -- Reply from 10.1.0.41: bytes=32 time=1028ms TTL=128

29/06/2009 12:38:29 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 12:38:35 PM -- Request timed out.
...
29/06/2009 12:39:24 PM -- Request timed out.
29/06/2009 12:39:27 PM -- Reply from 10.1.0.41: bytes=32 time=1445ms TTL=128

29/06/2009 1:08:14 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 1:08:20 PM -- Request timed out.
...
29/06/2009 1:09:09 PM -- Request timed out.
29/06/2009 1:09:12 PM -- Reply from 10.1.0.41: bytes=32 time=1772ms TTL=128

29/06/2009 1:38:27 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 1:38:33 PM -- Request timed out.
...
29/06/2009 1:39:22 PM -- Request timed out.
29/06/2009 1:39:26 PM -- Reply from 10.1.0.41: bytes=32 time=2554ms TTL=128

29/06/2009 2:08:23 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 2:08:28 PM -- Request timed out.
...
29/06/2009 2:09:19 PM -- Request timed out.
29/06/2009 2:09:22 PM -- Reply from 10.1.0.41: bytes=32 time=1921ms TTL=128

29/06/2009 2:38:29 PM -- Reply from 10.1.0.41: bytes=32 time<1ms ttl="">
29/06/2009 2:38:34 PM -- Request timed out.
...
29/06/2009 2:39:23 PM -- Request timed out.
29/06/2009 2:39:28 PM -- Reply from 10.1.0.41: bytes=32 time=3497ms TTL=128

(it continues)

So every 30 minutes there is a network outage of a minute or so on those guests. You'd say, 'hmm, hardware? cabling?', but NAY! Host pings reveal no timeouts, and other guests on the same host do not have the same timeouts. How weird is that???

Dan suggested that maybe the OS was coming into play, but when the problem initially occurred, there were a mix of 2008 and 2003 clients affected.

I'm going to run a Wireshark session on the LAN switch they are using, see if that comes up with something.

Update: The wireshark session hasn't really added too much to the proverbial pot here, especially since I can't figure out how to get a time range filtered out. Frame.time "" to frame.time "" doesn't seem to work.

Oh well, other issues to deal with for now.

Comments

Popular posts from this blog

DFSR - eventid 4312 - replication just won't work

This warning isn't documented that well on the googles, so here's some google fodder:


You are trying to set up replication for a DFS folder (no existing replication)Source server is 2008R2, 'branch office' server is 2012R2 (I'm moving all our infra to 2012R2)You have no issues getting replication configuredYou see the DFSR folders get created on the other end, but nothing stagesFinally you get EventID 4312:
The DFS Replication service failed to get folder information when walking the file system on a journal wrap or loss recovery due to repeated sharing violations encountered on a folder. The service cannot replicate the folder and files in that folder until the sharing violation is resolved.  Additional Information:  Folder: F:\Users$\user.name\Desktop\Random Folder Name\  Replicated Folder Root: F:\Users$  File ID: {00000000-0000-0000-0000-000000000000}-v0  Replicated Folder Name: Users  Replicated Folder ID: 33F0449D-5E67-4DA1-99AC-681B5BACC7E5  Replication Group…

Fixing duplicate SPNs (service principal name)

This is a pretty handy thing to know:

SPNs are used when a specific service/daemon uses Kerberos to authenticate against AD. They map a specific service, port, and object together with this convention: class/host:port/name

If you use a computer object to auth (such as local service):
MSSQLSVC/tor-sql-01.domain.local:1433

If you use a user object to auth (such as a service account, or admin account):
MSSQLSVC/username:1433

Why do we care about duplicate SPNs? If you have two entries trying to auth using the same Kerberos ticket (I think that's right...), they will conflict, and cause errors and service failures.

To check for duplicate SPNs:
The command "setspn.exe -X

C:\Windows\system32>setspn -X
Processing entry 7
MSSQLSvc/server1.company.local:1433 is registered on these accounts:
CN=SERVER1,OU=servers,OU=resources,DC=company,DC=local
CN=SQL Admin,OU=service accounts,OU=resources,DC=company,DC=local

found 1 groups of duplicate SPNs. (truncated/sanitized)

Note that y…

Logstash to Nagios - alerting based on Windows Event ID

This took way longer than it should have to get going...so here's a config and brain dump...

Why?
You want to have a central place to analyze Windows Event/IIS/local application logs, alert off specific events, alert off specific situations.  You don't have the budget for a boxed solution.  You want pretty graphs.  You don't particularly care about individual server states.  (see rationale below - although you certainly have all the tools here to care, I haven't provided that configuration)

How?
ELK stack, OMD, NXlog agent, and Rsyslog.  The premise here is as follows:

Event generated on server into EventLogNXlog ships to Logstash inputLogstash filter adds fields and tags to specified eventsLogstash output sends to a passive Nagios service via the Nagios NSCA outputThe passive service on Nagios (Check_MK c/o OMD) does its thing w. alerting
OMD
Open Monitoring Distribution, but the real point here is Check_MK (IIRC Icinga uses this...).  It makes Nagios easy to use and main…