[Linked Servers] Kerberos Double Hop - SPNs and Trusted for Delegation

Yesterday I ran into the dread Kerberos Double-Hop when trying to set up a linked server.  Thought it was the standard "Add an SPN using the Microsoft Kerberos Configuration tool".  Which didn't fix it.

What the....

Turns out there's another potential setting you have to fix. 

In active directory, the service account that SQL Server is running under may need this setting:

[Powershell] Tracking down that failing app on another server using WMI's win32_process and Profiler

(Yes, I'm still using profiler in some cases)

As we continue to move off SQL Server 2008, we've found instances where we change all the application configs, yet something on ServerA is still querying ServerB.  And since our internal application doesn't have the connection string set to give an ApplicationName, we have no idea which one is misconfigured - or if one was missed entirely!

1) Set up a profiler trace on one side, making sure to grab ClientProcessID

2) Run this WMI query on ServerA, using Powershell. 

$loopcount = 1

$futuretime = (get-date).addseconds(60)

$processeses = gwmi -Query "select caption, commandline, processid, name, executablepath from win32_process" # run locally on the server making the calls for speed)

do {

$processeses += gwmi -Query "select caption, commandline, processid, name, executablepath from win32_process" -ComputerName "mem-qa-trdb-17"

$loopcount++} while ((get-date) -lt $futuretime)

$processeses | ogv

(using $loopcount will tell you how many times it ran in that minute)

You could run it remotely if you had the proper WMI rights set up (which is probably the case on WS2016+), but my fear is that it'd be slow enough that it wouldn't "catch" the app as it's running, if it's spinning up on its own, failing to connect, then quitting. 

If the app is just running and not starting/stopping, then it'll keep the same PID (process_id) and you can just run the first $processeses and filter it. 

3) When the ogv (out-gridview) runs, it'll pop up an interactive window.  Type the actual number for ClientProcessID you got from the profiler trace, in the "filter" box, and it should filter down to just the Process (and location of the executable) that you need to fix.  

[EPR] Making the Extensible Powershell Repository work on a box with SQL Server 2017 since add-sqltable fails with Microsoft.SqlServer.Dmf

We're migrating the EPR (http://thebakingdba.blogspot.com/2013/04/servers-extensible-powershell.html) to a new box.  After 6 years, and it's still one of my best tools.  (Just drop a SQL or PS1 script in a folder, and it'll create a table and run it against all your servers).

Alas, Chad Miller's excellent add-sqltable started failing.  To the internet!

Could not load file or assembly 'Microsoft.SqlServer.Dmf"

Looking around, it appears that it's a problem with SMO.  On 2017, they split out SMO and SSMS.  Which means that installing SSMS 2017 doesn't get you SMO.  Supposedly installing it (install-module sqlserver) will do that, but I'd already did that and it wasn't working.

So, after fighting with it for a little bit, I decided to "get it working" and revisit later.

1) Install SSMS 2016 (which is when they started separating out SSMS)
2) Change the version from 11 to 13 in the script, as below: 

try {add-type -AssemblyName "Microsoft.SqlServer.ConnectionInfo, Version=13.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" -EA Stop}
catch {add-type -AssemblyName "Microsoft.SqlServer.ConnectionInfo"}

try {add-type -AssemblyName "Microsoft.SqlServer.Smo, Version=13.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" -EA Stop} 
catch {add-type -AssemblyName "Microsoft.SqlServer.Smo"} 

[Patching] Beware of SQL Server 2016 SP2 CU3 bug if running Replication and SA is not named SA!

TL;DR – if the SA account is not named SA (because, as per MS and Corporate, we rename it), this patch fails with this error and the server shuts down. 
(note the spots in bold).  Fix is to start the service with a T910 trace flag, rename that formerly-known-as-SA account to SA, then stop the service and start service back up via SERVICES.


Worth reading:
https://blog.sqlauthority.com/2018/04/04/sql-server-upgrade-error-alter-database-statement-not-allowed-within-multi-statement-transaction/

DESCRIBES THE PROBLEM AND SOLUTION:
https://feedback.azure.com/forums/908035-sql-server/suggestions/35805787-sql-server-2016-sp2-cu3-patch-breaks-if-replicatio

We just spent a good 30+ minutes trying to solve this.  Fortunately, after reading Pinal Dave’s post about it (top post), was able to figure out that I needed to google different terms, and found the above post which is far more applicable. (2nd link)

PREVENT:
Rename the SA account to SA before patching, at least for this specific patch. (2016 SP2 CU3)

THE FIX, if you patched and it doesn’t start back up:
1) From a command window, running AS ADMINISTRATOR, run this:
NET START MSSQLSERVER /T902
2) Connect via SSMS. Security->Logins, find the long-random-string-of-letters.  (Alternatively, find it in syslogins, but this appears simpler)
3) Right-click on the former-SA-account, and choose “Rename”
4) Rename to SA. 
5) Go back to the command window, run
NET STOP MSSQLSERVER /T902
6) Go back to the SERVICES, and start the SQL Service.  It should come up.

[Query Plan] Getting out the query execution plan when SP_whoisactive gives you a big fat NULL.

Ran into a problem where I couldn't get the execution plan for a query that was taking forever. 

Found a smarter man than me who'd build a powershell cmdlet to capture it and save it to disk.
http://www.patrickkeisler.com/2013/09/the-case-of-null-queryplan.html

Here's my wrapper for it:

$SPname = "yourspnamehere"
$servername = "yourserverhere"


. c:\powershell_scripts\invoke-sqlcmd2.ps1

$query = @"
SELECT master.dbo.fn_varbintohexstr(plan_handle) as plan_handle
FROM sys.dm_exec_cached_plans 
CROSS APPLY sys.dm_exec_sql_text(plan_handle) 
CROSS APPLY sys.dm_exec_query_plan(plan_handle)
WHERE 
text LIKE '%$SPname%'
AND objtype = 'Proc'
ORDER BY usecounts DESC;
"@

$queryresults = invoke-sqlcmd2 -serverinstance $servername -query $query
$planhandle = $queryresults.plan_handle
. z:\mydocs\get-queryplan.ps1 -SqlInstance "ods_scd" -planhandle "$planhandle"

[AWS] Powershell to figure out the encryption status of your EC2 drives.

since this turned out to be more difficult than I'd thought, posting it here.

$dbserver_instance = (Get-EC2Instance -Filter @{Name="tag:Name";Value="yourservernamehere"}  -Region us-east-1).Instances
get-ec2volume -filter @{Name="attachment.instance-id";value="$($dbserver_instance.instanceid)"} -region us-east-1

The tricky part is the tag:Name, which isn't obvious.  Also odd, if you just run the get-ec2volume with the tag:name and value, you get the exact same message as if you ran get-ec2instance!  I don't pretend to understand that.

[AWS RDS] Sending an email when there's a new version of RDS available

Something I needed recently.  Difficulty level: Get-RDSPendingMaintenanceAction ONLY returns info when there's something to be done.  If you're current, there's no way to find out what it looks like.

This will email you a HTML-formatted table with the details of each pending maintenance action for every instance in a region.

[AWS] Reading Aurora audit logs in Cloudwatch for DDL changes

Another form of log-watching, this time the Audit logs that Aurora can push to Cloudwatch.  It's not all stuff by any means; heck, the example they use is just about failed logins.

In this case, we're reading the Cloudwatch logs for our RDS clusters.
Since Cloudwatch offers filters, in this example we're looking for QUERY commands, since we've turned Server Audit on, and are uploading connects + queries to Cloudwatch.  (More information on that in: https://aws.amazon.com/blogs/database/monitoring-amazon-aurora-audit-events-with-amazon-cloudwatch/).  Remember to set a cap on it, though then interesting things could be buried.

Why are we doing this?  In our case, this gives us a few bits of cool info.  Specifically, we can log all the DDL commands that come across our cluster, making sure everything is behaving as expected.

[AWS] Aurora - reading the errorlog files with powershell

Been working on monitoring.  For some reason, when you tell Aurora to send errorlogs to Cloudwatch, all it sends are the Audit Logs, which will tell you that code had changed, etc, but doesn't (!?!?!??!!!) actually put your logs in Cloudwatch.  I don't understand it, so I built this process to look through logs and return the data.  The next step would be to format it and either upload to Cloudwatch manually, or log it, or send email.  Whatever works for you.  You be you.  :D

[AWS] powershell to patch all Aurora clusters

Pretty basic, but took longer than I figured it would.  The catch was figuring out how to look inside the results.


set-awscredentials -accesskey youraccesskey -secretkey yoursecretkey

Get-RDSPendingMaintenanceAction|%{
Submit-RDSPendingMaintenanceAction -ResourceIdentifier $_.ResourceIdentifier -applyaction $_.PendingMaintenanceActionDetails.action -OptInType immediate }


So when you get the results back, it looks like:

PendingMaintenanceActionDetails               ResourceIdentifier                                         
-------------------------------               ------------------                                         
{Amazon.RDS.Model.PendingMaintenanceAction}   arn:aws:rds:us-west-1:xxxxxxxx:cluster:xxxxxx

How do you view what's in that Amazon.RDS object?  I have no doubt there's some way to unpack it with powershell, but I'm not sure what that is.

What I did:

Looked at the PoSH module documentation for this cmdlet (Get-RDSPendingMaintenanceAction) to see what it returned:
https://docs.aws.amazon.com/powershell/latest/reference/Index.html

Which says:
PendingMaintenanceActionDetails
ResourceIdentifier

Which, indeed, is what it returned to us.

Now, clicking on the object info from the documentation:
System.Collections.Generic.List<Amazon.RDS.Model.PendingMaintenanceAction>

takes us to:
https://docs.aws.amazon.com/sdkfornet/v3/apidocs/index.html?page=RDS/TRDSResourcePendingMaintenanceActions.html&tocid=Amazon_RDS_Model_ResourcePendingMaintenanceActions)

And THAT page says it has Action, AutoAppliedAfterDate, etc.
When I run

$DataSet = Get-RDSPendingMaintenanceAction
$DataSet.PendingMaintenanceActionDetails

Here's what I get:

Action               : system-update
AutoAppliedAfterDate : 1/1/0001 12:00:00 AM
CurrentApplyDate     : 5/2/2018 4:41:00 PM
Description          : Aurora 1.17.2 release
ForcedApplyDate      : 1/1/0001 12:00:00 AM
OptInStatus          : immediate

So, now we have the fields we need: what kind of action to take (non optional, and it can be db-update or system-update), and the ResourceIdentifier for the cluster.