Deployment tools for Openstack have become very popular, including the very well known Openstack-Ansible. It makes deploying a Cloud an easy task, at the expense of losing access to the insights of "Behind the Scenes" of your your Cloud deployment. If you have had to configure neutron manually, you would have come across the following … Continue reading VNI Ranges: What do they do ?
Openstack Neutron provides by default some protections for your VMs' communications, those protections verify that VMs can not impersonate other VMs. You can easily see how it does that by checking the flow rules in an OVS deployment using: ovs-ofctl dump-flows br-int If you look for a certain qvo port (or the port number, depending … Continue reading Port security in Openstack
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From the title, this is obviously a very common scenario that you may want to do. One thing that we rarely think about though is "backends" for the attached volumes when we create volumes. When you create a volume, the volume is created on a cinder backend and kept attached to this backend until it's … Continue reading Migrating VMs with attached RBDs
Openstack stores quota usage for tenants in the database in quota_usages table. Nova and cinder have by default their own separate databases and in each database you get a new quota_usages table. The structure of the quota_usages table is as follows +---------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | … Continue reading Quota usage refresh in Openstack
Using CEPH as a backend for glance images has slowly become the default deployment methodology in many production deployments. It is usually as easy as creating a new pool in ceph ( glance pool) and creating a user to be associated with glance. The glance CEPH user will normally authenticate using cephx and store images … Continue reading Glance and CEPH backend
Cold migrations are an integral piece of any QEMU/KVM deployment. It's cold or "non-live" as you have to power down the VM, move it to the new host and power it back up. Openstack follows the same procedure when it comes to migrating VMs. Cold migrations in Openstack are done via the user running the … Continue reading VM Cold migrations/resizing in openstack
A tool that's less known-about for cinder is cinder-manage. You might have run into it during upgrades. The most common use case is cinder-manage db sync This is normally executed during upgrades to bring the database to the latest version, or to create the schema for a new installation. But there's actually additional usages for … Continue reading cinder-manage: Did you know about it ?