Quickref: The Ultimate Guide to Network Configuration and Troubleshooting for former-VKernel Virtual Appliances

Hello everyone!

Our virtual appliances only need Internet access for updates. As a result, we get a lot of networking-related queries when updates are available. I’m writing this guide in the hopes that it’ll help a few of you with the dreaded “Failed to check the update availability” message, among other things.

Accessing the Console

By default, the O/S has one user and root. The credentials are vkernel : vkernel and root : password

Please keep in mind that root logins are disabled over SSH by default. This means that if you’re connecting via some SSH client (like putty), you’ll have to login as vkernel. If you need root access from there, type su and hit enter. When prompted for a password, type the root password (listed above).

Most network-related changes in SuSE require root, so please be root when making any changes. Also, keep in mind that Linux is case-sensitive so don’t ignore case when typing these commands.

About VI

VI is a text editor that can be a little tricky to use if you’ve never done so before. The basics you’ll need to do most of what is required in this guide are as follows:

Hitting the i key when a document is open will enter ‘Insert Mode.’ When you’re in this mode you can just type to edit the text in the file. Otherwise, you’ll be giving commands to the program. To exit insert mode, just hit ESC.

If you are not in edit mode and want to save your changes, type :wq (colon write quit) and hit enter. If you’ve decided you’d prefer to quit without saving changes, type :q! (colon quit exclamation) and hit enter.

Changing Your IP

We have a script that gives you a nice little wizard where you can enter in your IP, Netmask, Gateway, etc.

Type the following into the command line and hit enter:

/usr/local/vkernel/scripts/changeIp.sh

Once you’ve finished the wizard and confirmed your settings, you can just restart networking:

/etc/init.d/network restart

Name Resolution

Sometimes you’ll want to enter multiple DNS entries and/or a search domain. Our script (above) doesn’t allow for this, but it’s very easy to modify:

vi /etc/resolv.conf

In here, you’ll want to enter information in this format:

search yoursearchdomain.com
nameserver ip.of.dns.1
nameserver ip.of.dns.2

If you intend on only using FQDN or IP when setting up or configuring the appliance’s connections to vCenter or an external database server, you can ignore search domain. This is for people who only want to enter a hostname and still have the resolution succeed.

Changing Hostname

Many like to modify the hostname to match what they set in their DNS:

vi /etc/HOSTNAME

Just change the default FQDN listed there to whatever it should be. After saving this, you must reboot the O/S for it to take effect. Do this to reboot:

shutdown -r now

Changing Proxy Settings

This can actually be done through the main UI. Go to Settings, General, Proxy to change this.

Ports

We know many of you have pretty strict firewall rules and need to explicitly whitelist certain IPs and ports to connect to the Internet. For us to update successfully, we'll need port 80access to the server ftp.vkernel.com to both check for and download updates.

Troubleshooting

More often than not, any error when trying to update the virtual appliance (such as "failed to check the update availability") boils down to the appliance not being able to contactftp.vkernel.com:80.

Not every network has ping enabled, so we're going to use telnet to troubleshoot.

First, just try this:

telnet ftp.vkernel.com 80

If you get ftp.vkernel.com: Unknown host as an error, please go to the Name Resolutionsection above and make sure your DNS servers are properly listed in resolv.conf.

If you get connection timed out or connection refused, it's probably a proxy or network firewall. See the Changing Proxy Settings section above or your network team.