https://docs.microsoft.com/archive/blogs/tzachiel/feed.xml Azure Blog Wed, 17 Apr 2019 03:27:20 GMT en-US hourly 1 https://docs.microsoft.com/archive/blogs/tzachiel/azure-linux-vm-restart-and-recover-a-non-responding-sshd Sat, 21 Jul 2018 21:34:07 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=445 Hello All, On today Scenario I will demonstrate how to recover from a non-responding SSHD. where you are not able to ssh and log to your VM. Sometimes it just not responding or got hang while our other bindings\listeners are working properly. All we want is to restart the daemon and avoid restarting the entire VM.   In this Demo I will show 3 options to recover from that scenario. Environment for this Test.

•  Ubuntu 18.04 TLS (but it can fit any Distro)
• Running Standard D4s v3 (4 vcpus, 16 GB memory)
• Premium SSD
• Accelerated networking: Enabled
• Provider: Azure Resource Manager (ARM)

  For this Demo I will kill the sshd Daemon (but we can use it when sshd is not responding or became unresponsive). Confirm SSHD is not Responding. Step by step instructions: Option 1.[Run command] 1.go to the Azure Portal and navigate to the VM Blade and go to "Run command" Enter the command [sudo service ssh restart]as you would on a console terminal and press Run.   And we are back In (the Output on the Portal will take some time). Option 2 [Serial Console] Navigate to the Azure Portal and navigate to the VM Blade and go to Serial Console (First let me Kill the new Process) Confirm SSHD is not Responding. Enter the command [sudo service ssh restart]as you would on a console terminal . Confirm ssh is enable and client can connect. Option 3 [Custom Script extension] Navigate to the Azure Portal and navigate to the VM Blade go the extensions and add Custom Script. Let's kill the process first. Confirm SSHD is not Responding. first let's create an SH file On my demo I used this name "restart_ssh.sh" use you favorite editor vi/nano etc. create a file and add the below. Content of the script [restart_ssh.sh]. #!/bin/bash #restart ssh Service sudo service ssh restart   Notice that on the Command we should run "sh" against our script file name. Confirm ssh is enable and client can connect.   If you get stuck during the Process or this debug is not for You. Please raise a ticket to Our Support and an engineer will be happy to assist mitigate the issue.   Thank You, Tzachi Elkabatz]]> https://docs.microsoft.com/archive/blogs/tzachiel/azure-windows-vm-rdp-port-got-disabled-on-ms-firewall Mon, 16 Jul 2018 22:32:11 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=295 for this Demo I have created a Rule to block RDP Requests. Once i press finish I got thrown from that session. Below we can see the connection got cut and we are not able to reach the VM via RDP.   Recover Steps:

• Navigate to Azure Portal
• Go to the VM facing that issue
• Select Extension and Press +ADD
• On you Desktop create a Files and insert the below

PS C:\Users\tzachie\Desktop> cat .\disable_MSFW_All_Profiles.ps1 Set-NetFirewallProfile -Profile Domain,Public,Private -Enabled False Save the Files as with any name you like i gave it this name disable_MSFW_All_Profiles.Ps1 Powershell Upload the Ps1 file you have created. Verify that the Extension was provisioned succeeded             Testing the Port from PowerShell Port is responsive. You should be able to RDP Now.   This is the current Firewall state (VM is at Risk) -Fix your Firewall rules soon as possible and Turn On MS Firewall.   Healthy  MS Firewall state. If you get stuck during the Process or this debug is not for You Please raise a ticket to Our Support and an engineer will help you to Mitigate the issue.   Thank You, Tzachi Elkabatz]]> https://docs.microsoft.com/archive/blogs/tzachiel/azure-linux-vm-configure-a-partition-larger-then-2-tb Sun, 21 Jan 2018 21:35:52 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=245 Below we can see what happens when trying to allocate one large partition that will contain the entire disk size. We will receive Value out of range. and disk we be partitioned as 1.8 TB. So here are the news ->Fdisk utility supports up to 2TB disk!! If you wish to use a larger disks please use parted utility.   So how do we overcome it ? We will use parted utility .   Hope this will help. if you still face an issue please raise a support ticket and one of our engineers will assist you. Thank You, Tzachi Elkabatz]]> https://docs.microsoft.com/archive/blogs/tzachiel/azure-linux-vm-cant-ssh Sun, 21 Jan 2018 21:06:12 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=195

1. Check if the VM is in Running State on the Portal.
2. Is there another Port exposed is it availably.(we are trying to isolate if there is a general network issue or just ssh is not responding)
3. If yes , Try to SSH the VM using it's DIP (Lan IP) from another running VM in the Same VNET. is this working
4. No , then please go to the Azure Portal and try to reset the SSH . Navigate to the VM blade and scroll down until you find the Reset Password.
5. Enable boot diagnostics (will generate serial log) and reboot the VM (look under or download to search for error)

first setup for boot diagnostics required a storage account configuration .     if you see an issue with Ssh configuration continue to the steps below.

• For RDFE\Azure VM Version 1 blade will appear like below.
• Option 1 : reset current user password or create a new login (will be granted permission to a shell and login)
• Option 2 : reset ssh keys in case you have lost your Privet key or it compromised

For our scenario we will go with Option 1      

• For ARM \Azure VM Version 2 blade will appear like below
• on Arm we have 3 options
• Option 1 : reset current user password or create a new login (will be granted permission to a shell and login).
• Option 2 : reset ssh keys in case you have lost your Privet key or it compromised.
• Option 3 : reset sshd_config (will copy a fresh config)

In this Scenario we will Try Option 3. if still we weren't able to reach the VM we can work on a console as we use to do on-premise . Create a Test VM in the same region that support virtualization and Mount the OS VHD( VM) to a hyper-v and investigate using console. Troubleshoot a Broken Azure VM using Nested Virtualization in Azure (RDFE) Troubleshoot a Broken Azure VM using Nested Virtualization in Azure (ARM) Troubleshoot a Broken Azure VM using Nested Virtualization in Azure (Managed Disk)  If you get stuck during the Process or this debug is not for You Please raise a ticket to Our Support and an engineer will help you to Mitigate the issue.   Thank You, Tzachi Elkabatz  ]]> https://docs.microsoft.com/archive/blogs/tzachiel/azure-linux-vm-apache-port-troubleshooting Thu, 17 Aug 2017 12:21:02 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=115

Make sure your binding is set to 0.0.0.0 and not restricted to 127.0.0.1 (by editing the httpd.conf) and verify by netstat -ntlp | grep 80  #port number you set your site.

 

1. Make sure you have allowed an Iptables rule to allow incoming requested for the Port you had set
2. If you are just testing disable Iptables to verify Site is working (For Ubuntu sudo ufw enable , For Centos/Redhat 6.x sudo service iptables stop ,For Centos/Redhat 7.x  systemctl disable firewalld
3. If you site doesn't reside on the defult apache\apache2 locationplease check Selinux (getenforce command)

1. you can temporary disable Selinux via the command  setenforce 0
2. To disabled Selinux you can edit the files /etc/Selinux and set to disable (Centos/Redhat this required a reboot)
3. On Ubuntu on Azure the package is not installed by default (selinux-utils)

 

1. after you verify your site is running and security rules are set or disabled you can try to browse the site from another VM running in the same VNET (NSG should be allowing this Port Requests)
2. Go to Azure Portal to your VM blade and navigate to the Network -- > NSG --> Open an allow rule to allow incoming traffic depend how you set your apache service.

 

1. Browse from External or use wget or curl command to check the page status.

 

1. You can always look at the syslog\messages logs for more information.
2. Or use Fiddler to get a page status.

  If this doesn't solve the Problem. Feel free to raise a ticket for our Azure Support and we will help you out. Thank You, Tzachi Elkabatz]]> https://docs.microsoft.com/archive/blogs/tzachiel/azure-linuxvm Wed, 16 Aug 2017 06:37:20 GMT https://blogs.msdn.microsoft.com/tzachiel/?p=45

Go to Azure Portal and Enabled Boot diagnostics. (This will expose the boot.log).

You need first to set an storage account to save the log and to checkbox the Boot diagnostics.

Reboot and refresh the Blade (do you see any errors on your boot.log ?).

 

• Did you change fstab  add new mounts /Disks and forgot to verify mount -a ? if yes then you will need to mount this vhd OS disk to a running Linux and correct your fstab .

• Did you push a new Extension ? Check on the Portal once the VM is running the Extensions Status.

If this Process didn't help. If this doesn't solve the Problem. Feel free to raise a ticket for our Azure Support and we will help you out. Thank You, Tzachi Elkabatz]]>