swift - containers?

asked 2020-04-14 00:29:40 -0500

happy75 gravatar image

Hi Openstack experts, My understanding is that swift is an object storage service. When you install the swift service, you will get a menu from the Openstack Dashboard to create containers. For the containers that are created through this means, do they exist on its own and not within a VM ? What is the difference between the container you manually created within a VM and the ones you created using swift?


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answered 2020-08-21 02:05:46 -0500

Darroncy gravatar image

swift has 3 kinds of server: account-server, container-server and object-server. The container-server will provide object-metadata(if applicable), mantain the lists of objects. All of these info will be stored in containerDB.

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answered 2020-04-14 01:57:25 -0500

A Swift container is a totally different concept than a Docker or LXC/LXD container. Like the difference between hair spray and democracy.

A Docker container or LXC/LXD container is used to protect an application from interference by other applications, and (in the case of Docker) allows "canned" application deployment.

A Swift container doesn't protect applications. It contains Swift objects. Swift containers are implemented on disk drives connected to storage nodes in a Swift cluster. In theory, those storage nodes can be virtual machines, but apart from test or proof-of-concept installations, Swift clusters are deployed on physical servers.

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Thanks very much for the detailed explanation! If I want to be able to create 10 virtual machines with lots of containers in them,which openstack service would be the best choice? Cinder or ceph?

happy75 gravatar imagehappy75 ( 2020-04-14 07:33:22 -0500 )edit

Neither Cinder nor Ceph create containers in VMs. Cinder manages storage volumes, Ceph is not an OpenStack service at all but manages huge storage clusters.

You can use Magnum to manage Kubernetes clusters (or Mesos or Docker Swarm clusters), which in turn manage Docker containers in VMs.

Bernd Bausch gravatar imageBernd Bausch ( 2020-04-14 08:44:21 -0500 )edit

thanks Bernd! I just had a look and magnum is another Openstack service https://docs.openstack.org/magnum/tra... So just to clarify, is the container created from magnum similar to the containers that you created manually within the openstack instances?

happy75 gravatar imagehappy75 ( 2020-04-14 19:46:16 -0500 )edit

can I also ask - does that mean without magnum you cannot create containers within the Openstack instances? sorry I am new to containers so please forgive my ignorance!

happy75 gravatar imagehappy75 ( 2020-04-14 19:58:18 -0500 )edit

You can create Docker containers on physical servers. You can create them on virtual servers. You can also create them on OpenStack instances.

Kubernetes, Mesos and Docker Swarm permit the management of servers that run containers. Magnum makes it easy to set up clusters of such servers.

Bernd Bausch gravatar imageBernd Bausch ( 2020-04-14 23:42:19 -0500 )edit

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Asked: 2020-04-14 00:29:40 -0500

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Last updated: Apr 14