Testing VMkernel network connectivity using vmkping

As we all know vmkernel adapters are critical when working with storage and  vmotion networks. Normally these networks are isolated from each other. So we can not rely only with the “ping” command. In that case, we should be able to ping from the specific adapter (ex: if storage related, need to use the specified vmkernel adapter [vmkX] to ping the storage system).

Will look at the steps,

Step 01 : SSH into the esxi host.

Step 02 : Identify the correct/relevant vmk, that has been mapped/assigned.

Step 03: Run the command in this format [vmkping -I vmkX x.x.x.x]

vmkis denoted by the vmkernel adapter number / x.x.x.x is denoted by the destination IP address.

How to Unlock ESXi hosts – you can not login at all

The root account of the ESXi hosts can be locked due to many failed login attempts. In this instance, you will not be able to connect to the host via web GUI or SSH. This can be due to many reasons, such as expired credentials / Brute force attacks and can cause Monitoring systems. Most of the time, I ended up with monitoring system related issues.

So, today we will look at the resolution steps.

There are requirements to be checked in advance following the below steps

Need physical console access or DCUI access (either using the iLO/iDRAC console)

The steps are as below (commands are in Italic and Bold)

1. Login to the DCUI console with the root credentials (do not worry you can access)

2. Enable SSH and shell access under the “Troubleshoot options”

3. Go to view logs and select syslogs and find the causing IP address

4. Then come back to DCUI main menu and press Alt + F1 to get the console

5. Execute the command pam_tally2 –user root to check how many failures and to identify the causing the IP address (in my case, the IP address of the monitoring system)

6. If you are confident on the source IP, you may unlock the root account by executing the pam_tally2 –user root –reset command

7. Just monitor for 15 minutes, if you notice re occurring failed attempts, you will have to change the IP or Power off the source (which we identified in step 3 & 5)

8. If you don’t notice any issues, you are good to go.