Ignition direct-lvm

[Douglas Davenport]

Can Ignition setup a second device to be used by the docker direct-lvm storage driver?

How should this be provisioned?

[Douglas Davenport]

On Sunday, January 22, 2017 at 10:30:37 AM UTC-5, Douglas Davenport wrote:

Can Ignition setup a second device to be used by the docker direct-lvm storage driver?

How should this be provisioned?

I'm very new to Container Linux and Ignition. Can someone please review what I have so far. Is there a better more idiomatic way to use Ignition for this type of provisioning?

I'm following the direct-lvm config approach described here: https://docs.docker.com/engine/userguide/storagedriver/device-mapper-driver/#configure-direct-lvm-mode-for-production

The following Ignition yaml seems to working:

storage:

  files:

    - path: /etc/lvm/profile/docker-thinpool.profile

      filesystem: root

      mode: 0644

      contents:

        inline: |

          activation {

              thin_pool_autoextend_threshold=80

              thin_pool_autoextend_percent=20

          }

    - path: /opt/init-direct-lvm

      filesystem: root

      mode: 0544

      contents:

        inline: |

          #!/bin/bash -ex

          /usr/sbin/wipefs -f /dev/sdb

          /usr/sbin/pvcreate -y /dev/sdb

          /usr/sbin/vgcreate -y docker /dev/sdb

          /usr/sbin/lvcreate --wipesignatures y -n thinpool docker -l 95%VG

          /usr/sbin/lvcreate --wipesignatures y -n thinpoolmeta docker -l 1%VG

          /usr/sbin/lvconvert -y --zero n -c 512K --thinpool docker/thinpool --poolmetadata docker/thinpoolmeta

          /usr/sbin/lvchange --metadataprofile docker-thinpool docker/thinpool

          /usr/sbin/lvs -o+seg_monitor

          /usr/bin/rm -rfv /var/lib/docker

systemd:

  units:

    - name: direct-lvm.service

      enable: true

      contents: |

        [Unit]

        Description=Configure device for docker direct-lvm storage driver

        ConditionFirstBoot=yes

        Before=docker.service

        [Service]

        Type=oneshot

        RemainAfterExit=yes

        ExecStart=-+/opt/init-direct-lvm

        [Install]

        RequiredBy=docker.service

    - name: docker.service

      dropins:

        - name: 10-direct-lvm.conf

          contents: |

            [Service]

            Environment="DOCKER_OPTS=--storage-driver=devicemapper --storage-opt dm.fs=ext4 --storage-opt=dm.thinpooldev=/dev/mapper/docker-thinpool --storage-opt=dm.use_deferred_removal=true --storage-opt=dm.use_deferred_deletion=true"

[Alex Crawford]

That seems reasonable. Just to be clear though, that config is a
Container Linux config which can be converted by the config-transpiler
(ct for short) [1] into an Ignition config.

-Alex

[1]: https://github.com/coreos/container-linux-config-transpiler