OpenShift 3.6 Generic Guest Template: Difference between revisions
| Line 89: | Line 89: | ||
==Docker Storage Setup== | ==Docker Storage Setup== | ||
Set up docker storage using Option A) described in the documentation: use an additional block device. In this case, the additional block device is provisioned as a dedicate volume group and exposed to the guest as the /dev/vdb block device. | |||
/etc/sysconfig/docker-storage-setup: | /etc/sysconfig/docker-storage-setup: | ||
Revision as of 05:07, 8 November 2017
Internal
Clone the Basic Template
Use the basic template as a base image, and clone it, as described here:
The particular sequence follows:
virsh shutdown ocp36.basic-template
virsh dumpxml ocp36.basic-template > /root/environments/ocp36/ocp36.basic-template.xml cp ocp36.basic-template.xml ocp36.generic-template.xml
Adjust the configuration as described here.
Clone the virtual machine image and create the new disk volumes, as described in Cloning a Guest.
virsh define /root/environments/ocp36/ocp36.generic-template.xml
virsh start --console ocp36.generic-template
Then reconfigure Linux VM Guest Image.
Install OpenShift Binaries
Attach the Node to the OpenShift Subscription
More details about subscription management:
The node, being based on the basic template, should have been already registered with the subscription manager:
subscription-manager status
subscription-manager identity
subscription-manager list --available --matches '*OpenShift*'
Identify the OpenShift pool ID:
subscription-manager attach --pool=<pool-id>
Manage Repositories and Install Utilities
Once attached to the pool, all repositories must be first disabled, and then only select repositories are re-enabled:
subscription-manager repos --disable="*"
subscription-manager repos --list-enabled yum repolist
If there are any enabled repositories, disable them with:
yum-config-manager --disable <repo_id>
Enable only the repositories required by OpenShift Container Platform 3.6:
subscription-manager repos --enable="rhel-7-server-rpms" --enable="rhel-7-server-extras-rpms" --enable="rhel-7-server-ose-3.6-rpms" --enable="rhel-7-fast-datapath-rpms"
subscription-manager repos --list-enabled yum repolist
yum update -y
Install atomic-openshift-utils, which contains OpenShift installer utilities and other tools required by the installation process:
yum install atomic-openshift-utils
At this point, no OpenShift binaries, except installation utilities, are installed. The advanced installer knows how to override this and it will install the binaries as expected, without any further intervention.
Install Docker
Install Docker on the generic template. On the support host, it will simply not be activated. Docker is also required on masters too, but the image storage allocated to it can be made much smaller than on the nodes and infranodes. The binaries must be installed from the rhel-7-server-ose-3.*-rpms repository and have it running before installing OpenShift.
OpenShift 3.6 requires Docker 1.12.
yum install docker docker version
Docker Storage Setup
Set up docker storage using Option A) described in the documentation: use an additional block device. In this case, the additional block device is provisioned as a dedicate volume group and exposed to the guest as the /dev/vdb block device.
/etc/sysconfig/docker-storage-setup:
CONTAINER_THINPOOL=docker-pool STORAGE_DRIVER=devicemapper DEVS=/dev/vdb CONTAINER_THINPOOL=container-thinpool VG=docker_vg ROOT_SIZE=50G DATA_SIZE=100%FREE MIN_DATA_SIZE=2G #POOL_META_SIZE=16M CHUNK_SIZE=512K GROWPART=false AUTO_EXTEND_POOL=yes POOL_AUTOEXTEND_THRESHOLD=60 POOL_AUTOEXTEND_PERCENT=20 DEVICE_WAIT_TIMEOUT=60 WIPE_SIGNATURES=true CONTAINER_ROOT_LV_SIZE=100%FREE # CONTAINER_ROOT_LV_MOUNT_PATH="/var/lib/containers/container-runtime"
docker-storage-setup
INFO: Volume group backing root filesystem could not be determined INFO: Device node /dev/vdb1 exists. Physical volume "/dev/vdb1" successfully created. Volume group "docker_vg" successfully created Using default stripesize 64.00 KiB. Rounding up size to full physical extent 52.00 MiB Thin pool volume with chunk size 512.00 KiB can address at most 126.50 TiB of data. Logical volume "container-thinpool" created. Logical volume docker_vg/container-thinpool changed.
The advanced installation procedure is supposed to update /etc/sysconfig/docker on nodes with OpenShift-specific configuration. The documentation says that the advanced installation procedure will add an "--insecure-registry" option, but that does not seem to be the case, so we add it manually in /etc/sysconfig/docker:
INSECURE_REGISTRY='--insecure-registry 172.30.0.0/16'
The subnet value used to configure the insecure registry corresponds to the default value of the services subnet.
Provision storage for the Docker server. The default loopback storage is not appropriate for production, it should be replaced by a thin-pool logical volume. Follow https://docs.openshift.com/container-platform/3.5/install_config/install/host_preparation.html#configuring-docker-storage. Used Option A) "an additional block device". On VirtualBox or KVM, provision a new virtual disk and install it. At this stage, the size it is not important, as it will replaced with the actual storage when the nodes are built. Use 100 MB for the template.
- Creating and installing a new virtual disk on VirtualBox
- Creating a new logical volume on KVM, followed by attachment to the template. When creating the logical volume, name it "template-docker.storage", following the storage volume naming conventions.
KVM example (the template VM must be shut down prior to attaching the storage):
virsh vol-create-as --pool main-storage-pool --name template-docker.raw --capacity 1024M virsh vol-list --pool main-storage-pool virsh attach-disk template /main-storage-pool/template-docker.raw vdb --config
Restart the template VM, the new storage should be available as /dev/vdb.
Then execute /usr/bin/docker-storage-setup with the base configuration read from /usr/lib/docker-storage-setup/docker-storage-setup and custom configuration specified in /etc/sysconfig/docker-storage-setup, similarly to:
STORAGE_DRIVER=devicemapper DEVS=/dev/vdb VG=docker_vg # set to a little bit less than maximum amount of space available DATA_SIZE=1023M MIN_DATA_SIZE=1M
Setting DATA_SIZE too small caused nodes not being able to start and OpenShift OutOfDisk events.
Execute:
/usr/bin/docker-storage-setup
Under some circumstances, /usr/bin/docker-storage-setup fails with:
[...] end of partition 1 has impossible value for cylinders: 65 (should be in 0-64) sfdisk: I don't like these partitions - nothing changed. (If you really want this, use the --force option.)
If this happens, use the patched docker-storage-setup available here: https://github.com/NovaOrdis/playground/blob/master/openshift/3.5/patches/node/usr/bin/docker-storage-setup
Before running it, remove any logical volume, volume group and physical volume that may have been created and leave an empty /dev/vdb1 partition. Then run
/usr/bin/docker-storage-setup --force
After the script completes successfully, it creates a logical volume with an XFS filesystem mounted on docker root directory /var/lib/docker and the Docker storage configuration file /etc/sysconfig/docker-storage. The thin pool to be used by Docker should be visible in lvs:
# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert docker-pool docker_vg twi-a-t--- 500.00m 0.00 0.88 root main_vg -wi-ao---- 7.00g
Alternatively, you can follow the manual procedure of provisioning Docker storage on a dedicated block device:
Disable docker-storage-setup, is not needed, storage already setup.
systemctl disable docker-storage-setup systemctl is-enabled docker-storage-setup
Enable Docker at boot and start it.
systemctl enable docker systemctl start docker systemctl status docker
Reboot the system and then check Docker Server Runtime.
TODO: parse and NOKB this: https://docs.openshift.com/container-platform/3.5/scaling_performance/optimizing_storage.html#optimizing-storage
Generic Docker installation instructions Docker Installation.