HAproxy short intro with example:
https://www.haproxy.com/blog/haproxy-configuration-basics-load-balance-your-servers/
Load balancer in RHEL
Advanced one:
https://www.digitalocean.com/community/tutorials/how-to-use-haproxy-to-set-up-http-load-balancing-on-an-ubuntu-vps
Editing networks using virsh
virsh net-edit somenetworkvirsh net-destroy somenetworkvirsh net-start somenetwork
Unless you destroy and start it again it won't be effect.
To verify the changes:
virsh net-dumpxml somenetwork
Creating storage pool using virsh:
virsh pool-create-as default dir --target /var/lib/libvirt/images
virsh pool-dumpxml default > storage-pool.xml
virsh pool-define storage-pool.xml
virsh pool-autostart default
Default username for fedora instance in AWS: fedora
For ubuntu OS, it is ubuntu.
For all others, ec2-user
Please refer AWS documentation for more authentic detail :)
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/managing-users.html
Copy/backup excluding specific file types:
rsync -av -e ssh --exclude='*.qcow2' <directory to copy> root@centos7:/home/username/
To delete a VM and its corresponding storage: (Use with caution you are deleting all the associated storage)
# virsh undefine --domain {VM_NAME_HERE} --remove-all-storage
To delete the snapshots too:
# virsh undefine --domain {VM_NAME_HERE} --delete-snapshots --remove-all-storage
Another safer approach is
# virsh list --all# virsh dumpxml {VM_NAME_HERE} // get the corresponding image.
# virsh undefine --domain {VM_NAME_HERE}
# rm -rf /path/to/image
I faced a error like this:
error: Refusing to undefine while domain managed save image exists
First run this command:
sudo virsh managedsave-remove --domain <domain name>
Next:
# virsh undefine --domain {VM_NAME_HERE} --remove-all-storage
If you face error saying "cannot define domain with nvram" use --nvram with above command.
# virsh undefine --nvram --domain {VM_NAME_HERE} --remove-all-storage
source: https://www.cyberciti.biz/faq/howto-linux-delete-a-running-vm-guest-on-kvm/