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Wanghua,

I don’t think moving flannel to the container is good idea. This is setup great for dev environment, but become too complex from operator point of view (you add extra Docker daemon and need extra Cinder volume for this daemon, also
keep in mind it makes sense to keep etcd data folder at Cinder storage as well because etcd is database). flannel has just there files without extra dependencies and it’s much easy to download it during cloud-init ;)

I agree that we have pain with building Fedora Atomic images, but instead of simplify this process we should switch to another more “friendly” images (e.g. Fedora/CentOS/Ubuntu) which we can easy build with disk builder.
Also we can fix CoreOS template (I believe people more asked about it instead of Atomic), but we may face similar to Atomic issues when we will try to integrate not CoreOS products (e.g. Calico or Weave)

―
Egor

From: 王华 <wanghua.humble at gmail.com<mailto:wanghua.humble at gmail.com>>
Reply-To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: Thursday, November 26, 2015 at 00:15
To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Subject: Re: [openstack-dev] [magnum]storage for docker-bootstrap

Hi Hongbin,

The docker in master node stores data in /dev/mapper/atomicos-docker--data and metadata in /dev/mapper/atomicos-docker--meta. /dev/mapper/atomicos-docker--data and /dev/mapper/atomicos-docker--meta are logic volumes. The docker in minion node store data in the cinder volume, but /dev/mapper/atomicos-docker--meta and /dev/mapper/atomicos-docker--meta are not used. If we want to leverage Cinder volume for docker in master, should we drop /dev/mapper/atomicos-docker--meta and /dev/mapper/atomicos-docker--meta? I think it is not necessary to allocate a Cinder volume. It is enough to allocate two logic volumes for docker, because only etcd, flannel, k8s run in the docker daemon which need not a large amount of storage.

Best regards,
Wanghua

On Thu, Nov 26, 2015 at 12:40 AM, Hongbin Lu <hongbin.lu at huawei.com<mailto:hongbin.lu at huawei.com>> wrote:
Here is a bit more context.

Currently, at k8s and swarm bay, some required binaries (i.e. etcd and flannel) are built into image and run at host. We are exploring the possibility to containerize some of these system components. The rationales are (i) it is infeasible to build custom packages into an atomic image and (ii) it is infeasible to upgrade individual component. For example, if there is a bug in current version of flannel and we know the bug was fixed in the next version, we need to upgrade flannel by building a new image, which is a tedious process.

To containerize flannel, we need a second docker daemon, called docker-bootstrap [1]. In this setup, pods are running on the main docker daemon, and flannel and etcd are running on the second docker daemon. The reason is that flannel needs to manage the network of the main docker daemon, so it needs to run on a separated daemon.

Daneyon, I think it requires separated storage because it needs to run a separated docker daemon (unless there is a way to make two docker daemons share the same storage).

Wanghua, is it possible to leverage Cinder volume for that. Leveraging external storage is always preferred [2].

[1] http://kubernetes.io/v1.1/docs/getting-started-guides/docker-multinode.html#bootstrap-docker
[2] http://www.projectatomic.io/docs/docker-storage-recommendation/

Best regards,
Hongbin

From: Daneyon Hansen (danehans) [mailto:danehans at cisco.com<mailto:danehans at cisco.com>]
Sent: November-25-15 11:10 AM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [magnum]storage for docker-bootstrap



From: 王华 <wanghua.humble at gmail.com<mailto:wanghua.humble at gmail.com>>
Reply-To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: Wednesday, November 25, 2015 at 5:00 AM
To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Subject: [openstack-dev] [magnum]storage for docker-bootstrap

Hi all,

I am working on containerizing etcd and flannel. But I met a problem. As described in [1], we need a docker-bootstrap. Docker and docker-bootstrap can not use the same storage, so we need some disk space for it.

I reviewed [1] and I do not see where the bootstrap docker instance requires separate storage.

The docker in master node stores data in /dev/mapper/atomicos-docker--data and metadata in /dev/mapper/atomicos-docker--meta. The disk space left is too same for docker-bootstrap. Even if the root_gb of the instance flavor is 20G, only 8G can be used in our image. I want to make it bigger. One way is we can add the disk space left in the vda as vda3 into atomicos vg after the instance starts and we allocate two logic volumes for docker-bootstrap. Another way is when we create the image, we allocate two logic volumes for docker-bootstrap. The second way has a advantage. It doesn't have to make filesystem when the instance is created which is time consuming.

What is your opinion?

Best Regards
Wanghua

[1] http://kubernetes.io/v1.1/docs/getting-started-guides/docker-multinode/master.html

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