Check the hash on a file using PowerShell

Posted in powershell by

Checking the hash of a file you’ve downloaded from the internet is very good practice. It’s a way to ensure the file you’re downloading hasn’t been tampered with, according to the hash provided on the site you’re downloading from.

Since Powershell 4.0, Get-FileHash has been a way to check the hash signature of a file.

A powershell windows showing the Get-FileHash command

Get-FileHash -Path C:\Path\to\file\file.exe -Algorithm SHA256

Get-FileHash can check the following signatures:

  • SHA1
  • SHA256 (default value)
  • SHA384
  • SHA512
  • MACTripleDES
  • MD4
  • RIPEMD160

Disks not visible to ESXi host

Posted in vSphere by

I have (4) new Dell PowerEdge R730xd Ready Nodes that I’m using for a new vSAN 6.6 cluster.

The systems are up to date on drivers and firmware. The controller is a PERC H730 mini, which is supported for pass-through. I installed the hypervisor on the SD card and checked to see if I could see the SSDs from vCenter. The drives weren’t visible.

SSD disks not visible to host

I SSH’d in the host and ran:

~ esxcli storage nmp device list

It only returned the SD card.

To get your disks to show up in your host, you have to reset the controller. First, put the host into maintenance mode.

Log into the iDRAC. Overview > Storage>Controller > Troubleshooting tab.

Under the actions drop down, select Reset Configuration.

Reset Controller in iDRAC

You’ll get a warning. Click OK to confirm.

System Alert Warning

Once the process is started, you can monitor the job queue’s progress.

When the reset is done,  you set the disks to Non-Raid.

Under Storage > Physical disks> Setup Tab, you click on the down arrow under Action-Assign to all.

Select Convert to Non-Raid and click apply. You can monitor the progress in the job queue.

Setting Physical Disks to Non-Raid Mode

Once it has completed, take the host out of maintenance mode and check the storage devices.

You should now be able to see all of your disks that are now available to the host for vSAN

Disks are now visible on the host.

Master Dead but PID File exists

Posted in Linux by

Users reported that mail stopped being sent from their server.

Tried to test email functionality from the command line.

# echo "Subject: Testing Sendmail from server.domain.com" | sendmail -v admin@domain.com
This is a test
BYE
[ctrl + D]

The message wasn’t sent. I tailed the maillog &  checked the service status:

# tail -n 500 /var/log/maillog
# service sendmail status
master dead by pid file exists

I checked to see if any Sendmail processes were running and there were several.

 ps -ef | grep sendmail

Stopped the service, deleted the master.pid and the lock file and killed all the sendmail processes, then restarted the sendmail service

# service sendmail stop
# rm /var/spool/postfix/pid/master.pid
# rm /var/lock/subsys/sendmail
# killall -9 sendmail
# service sendmail start
# service sendmail status

Tailed the logs, resent the email and it was delivered.

# watch tail -n 20 /var/log/maillog

 

Edit files from Windows Command Line

Posted in Windows by

I was adding entries to my hosts file on Windows 10 and I got an Access is Denied message when I saved the file in Notepad. Here are 2 quick ways to edit system files.

1) Right+Click Command Prompt or Notepad and Run as Administrator (old faithful)
2) From the Command Line, as Administrator,  start notepad.exe “hosts” (from the etc folder of course) or for more bang for your buck, open notepad++ with start notepad++.exe “hosts” if you have it installed.

Command to edit files from the command line

When you resize the wrong hard disk on a vm

Posted in disk partitioning, vmware by

I’m running WSUS on a 2012R2 server and the drive where the updates are tends to grow a lot. On this VM, I increased the provisioned size of the c:\ drive and not the  drive where the updates reside. I didn’t notice I’d touched the wrong disk until I’d rescanned the disks on the VM and saw what I’d done.

260gbdrive

 

As panic set in, I changed the provisioned size back to 60GB (I know, I know) and well, you know the rest. This article saved me today. I didn’t want to restore the VM unless I really had no choice, this did the trick.

wrongdisk

Power off the VM and identify the host & datastore that the VM resided on, I enabled SSH and browsed to the VM location.

Cat out the descriptor file  (vmname.vmdk) that outlines the data layout on the virtual disk. In the Extend Description section, you’ll see the extent(s) info. Next to RW (if it’s read/write) a number. That number represents the size of the vmdk in sectors, with the additional 200GB included.

extentsize

To change the sector size to reflect the value I’m shrinking the drive back down to, 60GB, calculate it:

60GB = 60 * 1024 * 1024 * 1024 / 512 = 125829120 sectors

Edit the descriptor file and change the sectors to the new number, save and exit.

newsectorsize.png

Come out of the directory where the VM resides and VMotion  it to another datastore. Review the settings of the vm and take note of the new and improved disk size.

newsize.png

Power on the VM and review the size in Disk Management.

diskmgnt

Now, grow the right disk and try not to ever do that again.

 

Error Applying Security- Access is Denied

Posted in server administration, Windows 2008 R2 by

Windows server administration is not without those DOH! moments. How is it that I, the administrator cannot change the permissions on a folder?

Access Denied Message

I will not be denied

The easiest way to fix this is to take ownership of the folder using the TAKEOWN command. Takeown is a tool that will allow an administrator to recover access to a file or folder that was denied by reassigning ownership. Open the command prompt and run as administrator.

takeown /f F:\FolderName /r /d y

/f  Specify the file name or directory

/r Recurse through all directories and sub directories

/d  Prompt with an answer of Yes

Now you can change the permissions as needed.

Windows Security Prompt

That’s more like it

Error when running WSUS post-installation task

Posted in Windows Server by

I have a newly installed Windows 2012 R2 server and I just added the Windows Server Update Service role. After the install completed, I launched the post-installation task.

Launch Post-Installation Tasks

The post install configuration failed. I reviewed the .tmp file to see what actually caused the task to fail.

CreateDefaultSubscription failed. Exception: System.Data.SqlClient.SqlException (0x80131904): Login failed for user USERID

Post-deployment Configuration

Details of failed task

tmplog

The user is the computer name of the WSUS server.

domain\servername$

I launched SQL Management Studio and located the user referenced in the log file.

After looking at the roles assigned to that database user, I then checked the SYSADMIN server role members and noticed the user mentioned is not listed.

databaseuser1

I added the computer name as a member and re-ran the post-installation task.

serverrollproperties

 That did the trick and the post deployment configuration completed without error.

configcomplete

*note*

I’m still testing to see if I can assign the computer a more restricted role other than sysadmin, and I haven’t found any documentation on it, but I’ll keep searching. Maybe I’ll tweet Lawrence Garvin.

Deprecated VMFS volumes found on the host Warning on ESXi after adding a datastore with Dell VSM

Posted in Storage, vmware by

I’m running ESXi version 6.1 U1 and Dell Virtual Storage Manager  (VSM)version 4.5.2.974. I added a datastore to  the cluster using VSM and on 2 of my hosts I got the following alert:

vsmversion

deprecatedvmfs

Enables SSH on the host and check out the logs.

In /var/log/hostd.log , I found the error:

 

 warning hostd[xXxXxX] [Originator@6876 sub=Hostsvc.DatastoreSystem opID=123456-789-abc-def user=vpxuser] UpdateConfigIssues: Deprecated VMFS filesystems detected. These volumes should be upgraded to the latest version.

When I created the datastore, I did select VMFS 5, so I wasn’t sure why this error appeared.

selectedvmfs5

According to vmware KB2109735, this is a known issue in version 6.0 and there is no resolution. Just restart the management services and the message goes away.

 

#  /etc/init.d/hostd restart
#  /etc/init.d/vpxa restart

Then the message goes away.

 

*note*

This only happens to me when I create a datastore with VSM. If I present a disk from my array, set up the iSCSI connections and rescan, I don’t get this message. Your mileage may vary.