OpenShift 3.6 Generic Guest Template: Difference between revisions

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* [[OpenShift_3.6_Installation#Guest_Template_Preparation|OpenShift 3.6 Installation]]
* [[OpenShift_3.6_Installation#Guest_Template_Preparation|OpenShift 3.6 Installation]]
=Overview=
The generic template contains all an OpenShift master or regular node, as well as the support node, need to function. It is built in top of the [[OpenShift_3.6_Basic_Guest_Template#Overview|basic template]].


=Clone the Basic Template=
=Clone the Basic Template=


Use the [[OpenShift_3.6_Basic_Guest_Template|basic template]] as a base image, and clone it, as described here:
Use the [[OpenShift_3.6_Basic_Guest_Template#Overview|basic template]] as a base image, and clone it, as described here:


{{Internal|Linux Virtualization Cloning a KVM Guest Virtual Machine|Cloning a Guest}}
{{Internal|Linux Virtualization Cloning a KVM Guest Virtual Machine|Cloning a Guest}}


The particular sequence follows:
The process will produce a ocp36.generic-template.
 
=Install OpenShift Binaries=
 
==Attach the Node to the OpenShift Subscription==
 
{{External|https://docs.openshift.com/container-platform/3.6/install_config/install/host_preparation.html#host-registration}}
 
More details about subscription management:
 
{{Internal|Red_Hat_Subscription_Manager#Register_a_Linux_System|RedHat Subscription Manager}}
 
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:


  virsh shutdown ocp36.basic-template
  yum install atomic-openshift-utils


virsh dumpxml ocp36.basic-template > /root/environments/ocp36/ocp36.basic-template.xml
{{Warn|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.}}
cp ocp36.basic-template.xml ocp36.generic-template.xml


Adjust the configuration as described [[Linux_Virtualization_Cloning_a_KVM_Guest_Virtual_Machine#Adjust_the_Configuration|here]].
=Install Docker=


Clone the virtual machine image and create the new disk volumes, as described in [[Linux Virtualization Cloning a KVM Guest Virtual Machine|Cloning a Guest]].
{{External|https://docs.openshift.com/container-platform/3.6/install_config/install/host_preparation.html#installing-docker}}


virsh define /root/environments/ocp36/ocp36.generic-template.xml
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.  


virsh start --console ocp36.generic-template
OpenShift 3.6 requires Docker 1.12.


Then [[Reconfigure Linux VM Guest Image|reconfigure Linux VM Guest Image]].
yum install docker
docker version


=Install OpenShift Binaries=
==Docker Storage Setup==


==Attach the Node to the OpenShift Subscription==
<font color=red>Process: https://docs.docker.com/storage/storagedriver/device-mapper-driver/#configure-direct-lvm-mode-for-production</font>


Attach the node to the subscription, using subscription manager, as described here: [[Red_Hat_Subscription_Manager#Register_a_Linux_System|registering a RHEL System with subscription manager]]. The support node(s) need only a Red Hat Enterprise Linux. The OpenShift nodes need an OpenShift subscription. For OpenShift, follow these steps: https://docs.openshift.com/container-platform/3.6/install_config/install/host_preparation.html#host-registration.
Provision [[OpenShift_Concepts#Docker_Storage_in_OpenShift|storage for the Docker server]]. The [[Docker_Concepts#Loopback_Storage|default loopback storage]] is not appropriate for production, it should be replaced by a [[Linux_Logical_Volume_Management_Concepts#Thinly-Provisioned_Logical_Volumes_.28Thin_Volumes.29|thin-pool logical volume]]. 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 50GB dedicate volume group and exposed to the guest as the /dev/vdb block device.


The the summary of the sequence of steps is available below - the goal of these steps is to configure the following supported repositories on the system: "rhel-7-server-rpms", "rhel-7-server-extras-rpms", "rhel-7-server-ose-3.5-rpms", "rhel-7-fast-datapath-rpms":
/etc/sysconfig/docker-storage-setup:


<pre>
<pre>
subscription-manager register
CONTAINER_THINPOOL=docker-pool
subscription-manager list --available --matches '*OpenShift*'
STORAGE_DRIVER=devicemapper
subscription-manager attach --pool=<pool-id> --quantity=1
DEVS=/dev/vdb
subscription-manager repos --disable="*"
CONTAINER_THINPOOL=container-thinpool
subscription-manager repos --list-enabled
VG=docker_vg
yum repolist
ROOT_SIZE=50G
yum-config-manager --disable <repo_id>
DATA_SIZE=100%FREE
subscription-manager repos --enable="rhel-7-server-rpms" --enable="rhel-7-server-extras-rpms" --enable="rhel-7-server-ose-3.5-rpms" --enable="rhel-7-fast-datapath-rpms"
MIN_DATA_SIZE=2G
subscription-manager repos --list-enabled
#POOL_META_SIZE=16M
yum repolist
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"
</pre>
</pre>


* Install base packages (https://docs.openshift.com/container-platform/3.5/install_config/install/host_preparation.html#installing-base-packages):
{{Warn|Setting DATA_SIZE too small caused nodes not being able to start and OpenShift [[OpenShift Concepts#OutOfDisk|OutOfDisk events]].}}
 
If this is template reconfiguration, remove previous Docker metadata:
 
  rm -r /var/lib/docker
  cat /dev/null > /etc/sysconfig/docker-storage
 
Execute:
 
/usr/bin/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.
 
lvs
  LV                VG        Attr      LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  container-thinpool docker_vg twi-a-t--- 49.89g            0.00  0.11
 
After setup, disable docker-storage-setup at startup, is not needed, storage already setup.
 
  systemctl disable docker-storage-setup
  systemctl is-enabled docker-storage-setup
 
==Docker and OpenShift Installation==
 
The OpenShift advanced installation procedure is supposed to update [[Docker_Server_Configuration#RedHat.2FCentos|/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 based on previous installation experience, we learned to add it manually in /etc/sysconfig/docker:
 
OPTIONS=' --selinux-enabled  --log-driver=journald <font color=teal>'''--insecure-registry 172.30.0.0/16'''</font>'
 
The subnet value used to configure the insecure registry corresponds to the default value of the [[OpenShift_Concepts#The_Services_Subnet|services subnet]].
 
==Test Start Docker==
 
Enable docker to start at boot:


<pre>
systemctl enable docker
yum update -y
systemctl start docker
yum install atomic-openshift-utils
 
</pre>
Reboot the system and then check [[Docker Server Runtime]].
 
=Optimizing Docker Storage=
 
{{External|https://docs.openshift.com/container-platform/3.6/scaling_performance/optimizing_storage.html#optimizing-storage}}
 
==Prevent Docker to Start at Boot==
 
We do not want the template to start docker at boot, because in some cases we may want to modify the storage depending on the node's particularities.
 
Also we do not want to automatically start, because we may want to configure new storage manually.
 
  systemctl disable docker
  systemctl is-enabled docker
 
  systemctl disable docker-storage-setup
  systemctl is-enabled docker-storage-setup

Latest revision as of 20:37, 20 April 2018

Internal

Overview

The generic template contains all an OpenShift master or regular node, as well as the support node, need to function. It is built in top of the basic template.

Clone the Basic Template

Use the basic template as a base image, and clone it, as described here:

Cloning a Guest

The process will produce a ocp36.generic-template.

Install OpenShift Binaries

Attach the Node to the OpenShift Subscription

https://docs.openshift.com/container-platform/3.6/install_config/install/host_preparation.html#host-registration

More details about subscription management:

RedHat Subscription Manager

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

https://docs.openshift.com/container-platform/3.6/install_config/install/host_preparation.html#installing-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

Process: https://docs.docker.com/storage/storagedriver/device-mapper-driver/#configure-direct-lvm-mode-for-production

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. 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 50GB 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"

Setting DATA_SIZE too small caused nodes not being able to start and OpenShift OutOfDisk events.

If this is template reconfiguration, remove previous Docker metadata:

 rm -r /var/lib/docker
 cat /dev/null > /etc/sysconfig/docker-storage

Execute:

/usr/bin/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.
lvs
 LV                 VG        Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
 container-thinpool docker_vg twi-a-t--- 49.89g             0.00   0.11

After setup, disable docker-storage-setup at startup, is not needed, storage already setup.

 systemctl disable docker-storage-setup
 systemctl is-enabled docker-storage-setup

Docker and OpenShift Installation

The OpenShift 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 based on previous installation experience, we learned to add it manually in /etc/sysconfig/docker:

OPTIONS=' --selinux-enabled  --log-driver=journald --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.

Test Start Docker

Enable docker to start at boot:

systemctl enable docker
systemctl start docker

Reboot the system and then check Docker Server Runtime.

Optimizing Docker Storage

https://docs.openshift.com/container-platform/3.6/scaling_performance/optimizing_storage.html#optimizing-storage

Prevent Docker to Start at Boot

We do not want the template to start docker at boot, because in some cases we may want to modify the storage depending on the node's particularities.

Also we do not want to automatically start, because we may want to configure new storage manually.

 systemctl disable docker
 systemctl is-enabled docker
 systemctl disable docker-storage-setup
 systemctl is-enabled docker-storage-setup