virtualization | Chris Titus Tech

How to Install Xen Orchestra

Thu, 11 Oct 2018 17:14:47 GMT

This article shows you how to install Xen Orchestra and use the interface via the web. XOA is a very powerful addition to XenServer as it brings auto-updates and making it easier to manage entire farms.

Step-by-Step Guide

Login to your XenServer via PuTTy OR through XenCenter console
Type bash -c "$(curl -s http://xoa.io/deploy)"
- Enter a new IP where you will access XOA from web
- Wait for this to finish you will see XOA VM popup
- Note: This may take a couple hours if XOA servers are downloading slow. I highly recommend downloading offline installer if installing on multiple servers.
Once Complete, PuTTy to XOA VM (IP Address from prior install)
- login with username/password: xoa
- set new password for console
- register xoa from username and password that you used on their website https://xen-orchestra.com/
  - sudo xoa-updater --register
- now run the updater to check for any upgrades
  - sudo xoa-updater –upgrade
- reboot if any upgrades were performed
Open Browser, Login to XOA
- login username admin@admin.net password admin
Add your XenServers – If you only have 1 pool, you only need to add your pool master
- Remember: if you are using default self-signed certificates on XenServer enable “unauthorized certificates” and then click disconnected
Enjoy

Video Walkthrough

I hope you enjoyed this walkthrough of how to install Xen Orchestra and if you have any feedback let me know below. In closing, I really like this product and think it is a great addition to the XenServer and a much-needed improvement over what Citrix offers.

Create iSCSI SR in XenServer

Tue, 09 Oct 2018 16:18:46 GMT

This guide goes over how to Create iSCSI SR on Xen to connect to an iSCSI target. Here is the step-by-step and a video walkthrough, which includes setting up iSCSI in FreeNAS.

Requirements

Multiple XenServers (2+) in a Pool
iSCSI target (Check out FreeNAS in the video below for setting one up)
At LEAST a gigabit environment

Step-by-Step Guide to Create iSCSI SR

Open and Connect to XenCenter / XCP-ng Center
Select Pool and Click New Storage
Make sure iSCSI is selected
Name Storage
Select either provisioning methods
Enter IP Address / Authentication (if needed) / Click Scan Target Host
Pick IQN / LUN from your storage device
- Note: When Selecting IQN_, make sure you select your SAN if you are using a dedicated network_
Finish

Video Walkthrough

In the end, we now have a centralized storage system that all our hosts can put their VMs on. This is key for using high availability, Xen Orchestra, and quick migrations. Remember to use the community-driven XenServer @ https://xcp-ng.org/, therefore you can get all the enterprise features of XenServer in your lab environment.

XenServer cannot connect in XenCenter or XCP-ng Center

Mon, 01 Oct 2018 18:53:13 GMT

Having problems and your XenServer cannot connect to XenCenter? Did you have high availability enabled? If you answered yes to both these questions here is how you get your XenServer back online and functioning properly.

Step-by-Step Guide

PuTTy into the XenServer Pool Master
run the following commands:

xe pool-ha-disableNote: If this fails try ha-disable force below

xe host-emergency-ha-disable force=true<br /> xe pool-emergency-transition-to-master --force

Note: This will force the pool and slaves to reinitialize with the pool master

Once the server reboots it should connect
Go into your XenCenter and re-connect

Other Helpful Commands for troubleshooting

xe-toolstack-restart – First command I always try before anything else

service xapi restart – This restarts a core service

xsconsole – This launches console to check pool, network config, ha, running VMS, etc.

How-To Video going over troubleshooting

Conclusion

This will get your server back up and accessible, however, this disables high availability and will need to be set back up. It’s important to note the cause of an event like this. In my case, the SR I was using to host my VMs was not sufficient and caused the outage. If this happens to you make sure you have a good SAN/NAS for hosting on a Gigabit or above connection. I’d highly recommend a 10Gbs connection or a multipath gigabit connection at the very least.

Introduction to Google Cloud Platform

Tue, 11 Sep 2018 13:44:02 GMT

This is an Introduction to Google Cloud Platform and goes over creating your first project and virtual machine. This walkthrough is for beginners that are just getting started with Google Cloud.

Video Walkthrough

GCloud Commands

Allows gcloud commands from command prompt

https://cloud.google.com/appengine/docs/standard/python/download

Next Steps

Now that we know how to use Google Cloud Platform, go out and build up your first system. I highly recommend starting with an Ubuntu server, since they have the best community support for starters, and install a web server to host a website. I found this incredibly easy, especially compared to AWS or Azure. If you want to see any follow-up topics on Google Cloud Platform, let me know below, and I will work on creating more content explaining it. If you are in business, I highly recommend you look at Google Cloud Platform for a backup server and use a VPN to connect your on-site servers. This works seamlessly and is very affordable for a cloud solution.

XCP-ng / XenServer – Your First Virtual Machine Installation

Sun, 09 Sep 2018 18:54:21 GMT

This video goes through setting up a Virtual Machine in XenServer / XCP-ng in a lab environment. If you want to experiment with in detail with XenServer, I highly recommend you download XCP-ng from their official website. This is a community-powered version of XenServer with ALL FEATURES ENABLED. XenServer from Citrix has recently started going away from its open-source roots and as a result, has begun locking features behind a paywall.

Virtualization Introduction

Fri, 07 Sep 2018 21:33:35 GMT

This is a virtualization introduction and when you should be using it. In the follow-up videos, I will go into using the hypervisor, creating VMs and maintenance.

Now that you understand what it is and if you want to start getting your feet wet, check out my other videos about installing a hypervisor and launching your first virtual machine. I highly recommend starting out with VMware as it used the most. It also has the most material online if looking for virtualization introduction videos and how to guides.

Commiting Changes to Docker images and containers

Thu, 21 Jun 2018 19:36:03 GMT

This is a walkthrough of how to commit changes to docker images and containers. You need to do this if you make configuration changes to any docker images. By committing changes to the docker images you can backup and clone them.

Docker is a very powerful tool you can use to isolate applications, therefore, you won’t have them on a single server. However, some docker images don’t save changes to their container when a restart happens. You will notice that when a reboot or unexpected outage happens all your configuration will be gone since the creation of container. The Ubiquiti Unifi Controller docker image is a good example of this.

Here are the following commands to commit those changes to a new image

sudo docker ps -l
Note: This shows all your containers you need to copy Container ID for the one you want to commit changes on.

sudo docker commit CONTAINER_ID_GOES_HERE IMAGENAME:TAG
Example Syntax: sudo docker commit 520b0f024bf6 unifi:latest-06-21-2018

Now if you have any issues you can simply create a new container using the image you created above.

Reattach LVM after a reinstalling XenServer

Wed, 03 Aug 2016 16:18:32 GMT

This article describes how to reattach LVM or a local Storage repository on XenServer. The XenServer database has become corrupt or your XenServer does not see the local SR.

Instructions

Do a pvscan to get the Universally Unique Identifier (UUID) of an existing SR on a local disk. In this example uses UUID 39baf126-a535-549f-58d6-feeda55f7801:

pvscan

Output

PV /dev/sda3 VG VG_XenStorage-39baf126-a535-549f-58d6-feeda55f7801 lvm2 [66.87 GB / 57.87 GB free]
Total: 1 [66.87 GB] / in use: 1 [66.87 GB] / in no VG: 0 [0 ]

Note the output above, the VG name of the local drive /dev/sda3 is VG_XenStorage-39baf126-a535-549f-58d6-feeda55f7801 . The VG name contains the SR UUID that resides on this storage media. In this case, the UUID is 39baf126-a535-549f-58d6-feeda55f7801.

Introduce the SR with the following command:

xe sr-introduce uuid=39baf126-a535-549f-58d6-feeda55f7801 type=lvm name-label=”Local storage” content-type=user

This command sets up database records for the SR named “Local storage”
Locate the SCSI ID of the device or partition where the SR data is stored:

ls -l /dev/disk/by-id/

SCSI ID Output

total 0
lrwxrwxrwx 1 root root 9 Jan 15 09:44 scsi-SATA_ST3500320AS_9QM13WP2 -> ../../sdb
lrwxrwxrwx 1 root root 10 Jan 15 09:44 scsi-SATA_ST3500320AS_9QM13WP2-part1 -> ../../sdb1
lrwxrwxrwx 1 root root 9 Jan 15 09:44 scsi-SATA_ST380815AS_6QZ5Z1AM -> ../../sda
lrwxrwxrwx 1 root root 10 Jan 15 09:44 scsi-SATA_ST380815AS_6QZ5Z1AM-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Jan 15 09:44 scsi-SATA_ST380815AS_6QZ5Z1AM-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Jan 15 09:44 scsi-SATA_ST380815AS_6QZ5Z1AM-part3 -> ../../sda3

_In this case, the SCSI ID of the device /dev/sda3 is scsi-SATA_ST380815AS_6QZ5Z1AM-part3.

Notate the device name to use in the next command, where a PBD (physical block device – a connector between the XenServer host and the SR) is created._

Run the xe host-list command to find out the host UUID for the local host:

xe host-list

uuid ( RO) : 83f2c775-57fc-457b-9f98-2b9b0a7dbcb5
name-label ( RW): xenserver1
name-description ( RO): Default install of XenServer

Create the PBD using the device SCSI ID, host UUID and SR UUID detected above:

xe pbd-create sr-uuid=39baf126-a535-549f-58d6-feeda55f7801 device-config:device=/dev/disk/by-id/scsi-SATA_ST380815AS_6QZ5Z1AM-part3 host-uuid=83f2c775-57fc-457b-9f98-2b9b0a7dbcb5

Afterward, it displays: aec2c6fc-e1fb-0a27-2437-9862cffe213e

Attach the PBD created with xe pbd-plug command:

xe pbd-plug uuid=aec2c6fc-e1fb-0a27-2437-9862cffe213e

In the end, you now have reattach LVM to the XenServer host and be visible in XenCenter.

Source: Original Article from Citrix http://support.citrix.com/article/CTX121896

XenServer tapdisk experienced an error

Wed, 03 Aug 2016 16:12:57 GMT

When re-attaching a SR on a fresh VM, I ran into this XenServer tapdisk error. I ran the following from XenServer console to eject all CD drives on that host. I was then able to start the VM with the old image.

xe vm-cd-eject --multiple

If your XenCenter hangs or becomes unresponsive, you can also reset the toolstack from console from a PuTTy session or if XenCenter console is working running the following command:

xe-toolstack-restart

It’s important to note what caused the XenServer tapdisk error. I experienced this on an old version of XenServer 6 when switching out the ISOs from the VMs.

Citrix XenCenter error “Could not create SSL/TLS Secure Channel”

Wed, 13 Jul 2016 14:24:04 GMT

Running the following commands will fix the XenCenter Error. You are typically encountering this error because Windows 10 requires stronger encryption, consequently, this is prevalent on older XenServer installations. I encountered this on XenServer 6.0.

Commands

Putty in using SSH

service xapissl stop
mv /etc/xensource/xapi-ssl.pem /etc/xensource/xapi-ssl.pem.bak
/opt/xensource/libexec/generate_ssl_cert "/etc/xensource/xapi-ssl.pem" '10.100.0.40'
service xapissl start
xe-toolstack-restart

Where you see 10.100.0.40 this is the IP of your XenServer that you are connecting to (not VM ips). Once you run this it reissues the cert and you will be able to properly connect. I’ve seen this on Windows 10 Systems since they force the higher level encryption, however, If this doesn’t resolve the XenCenter error let me know.