Skip to main content

Quick update - mysql & SNMP

Last night I also got a mysql VM and syslog VM up.  After the wiki issue, I figured now was a good time to get the database off the wiki server and onto a dedicated mysql server.  That server will then back up onto the NAS - something that will help me sleep better at night.  The dedicated mysql box is also pretty key for a number of other Linux applications.

I am not certain yet if I should be running postgresql and mysql on the same VM (even though there will be separate VMDKs for DBs, logs, temp, etc (wrong terminology??)).  At any rate, once that's ready and documented, I can really get cracking.  Can't wait to get the Nagios box online as well.

Speaking of which, I've learned a lot about SNMP lately.  The process from trap to Nagios alert is quite involved:
  1. Trap to Nagios host
  2. snmptrapd receives trap
  3. snmptrapd formats trap as per snmptt
  4. snmptt logs the trap and looks up what happens
  5. snmptt runs the EXEC line which submits the result to Nagios
I'd have to consult my documentation for more detail, but that's the gist of it.  Also learned some handy SNMP troubleshooting tips:
  • Use the snmptt debug to get a clear picture of what's going on
  • If you get 'unknown' traps logged, chances are your MIB is outdated or not present
  • Ensure logging is turned on and log directories are correctly specified
  • You can use the net-snmp-tools to manually send a trap from your workstation
Yep, good stuff.  I'll add an SNMP section to the wiki at some point.


Anyways, next step is configuring and documenting the mysql/postgresql VM.

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…