From 8e7c5c970b8adc83fd6d5cad115f4edb06b36d98 Mon Sep 17 00:00:00 2001 From: Scott Dodson Date: Mon, 5 Oct 2015 12:53:10 -0400 Subject: Containerization work by @sdodson --- README_CONTAINERIZED_INSTALLATION.md | 101 +++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 README_CONTAINERIZED_INSTALLATION.md (limited to 'README_CONTAINERIZED_INSTALLATION.md') diff --git a/README_CONTAINERIZED_INSTALLATION.md b/README_CONTAINERIZED_INSTALLATION.md new file mode 100644 index 000000000..5f51b9507 --- /dev/null +++ b/README_CONTAINERIZED_INSTALLATION.md @@ -0,0 +1,101 @@ +# Overview + +Users may now deploy containerized versions of OpenShift Origin, OpenShift +Enterprise, or Atomic Enterprise Platform on Atomic +Host[https://projectatomic.io] or RHEL, Centos, and Fedora. This includes +OpenvSwitch based SDN. + + +## Installing on Atomic Host + +When installing on Atomic Host you will automatically have containerized +installation methods selected for you based on detection of _/run/ostree-booted_ + +## Installing on RHEL, Centos, or Fedora + +Currently the default installation method for traditional operating systems is +via RPMs. If you wish to deploy using containerized installation you may set the +ansible variable 'containerized=true' on a per host basis. This means that you +may easily deploy environments mixing containerized and RPM based installs. At +this point we suggest deploying heterogeneous environments. + +## CLI Wrappers + +When using containerized installations openshift-ansible will deploy a wrapper +script on each master located in _/usr/local/bin/openshift_ and a set of +symbolic links _/usr/local/bin/oc_, _/usr/local/bin/oadm_, and +_/usr/local/bin/kubectl_ to ease administrative tasks. The wrapper script spawns +a new container on each invocation so you may notice it's slightly slower than +native clients. + +The wrapper scripts mount a limited subset of paths, _~/.kube_, _/etc/origin/_, +and _/tmp_. Be mindful of this when passing in files to be processed by `oc` or + `oadm`. You may find it easier to redirect input like this : + + `oc create -f - < my_file.json` + +## Technical Notes + +### Requisite Images + +Based on your deployment_type the installer will make use of the following +images. Because you may make use of a private repository we've moved the +configuration of docker additional, insecure, and blocked registries to the +beginning of the installation process ensuring that these settings are applied +before attempting to pull any of the following images. + + Origin + openshift/origin + openshift/node (node + openshift-sdn + openvswitch rpm for client tools) + openshift/openvswitch (centos7 + openvswitch rpm, runs ovsdb ovsctl processes) + registry.access.redhat.com/rhel7/etcd + OpenShift Enterprise + openshift3/ose + openshift3/node + openshift3/openvswitch + registry.access.redhat.com/rhel7/etcd + Atomic Enterprise Platform + aep3/aep + aep3/node + aep3/openvswitch + registry.access.redhat.com/rhel7/etcd + + * note openshift3/* and aep3/* images come from registry.access.redhat.com and +rely on the --additional-repository flag being set appropriately. + +### Starting and Stopping Containers + +The installer will create relevant systemd units which can be used to start, +stop, and poll services via normal systemctl commands. These unit names match +those of an RPM installation with the exception of the etcd service which will +be named 'etcd_container'. This change is necessary as currently Atomic Host +ships with etcd package installed as part of Atomic Host and we will instead use +a containerized version. The installer will disable the built in etcd service. +etcd is slated to be removed from os-tree in the future. + +### File Paths + +All configuration files are placed in the same locations as RPM based +installations and will survive os-tree upgrades. + +The examples are installed into _/etc/origin/examples_ rather than +_/usr/share/openshift/examples_ because that is read-only on Atomic Host. + + +### Storage Requirements + +Atomic Host installs normally have a very small root filesystem. However the +etcd, master, and node containers will persist data in /var/lib. Please ensure +that you have enough space on the root filesystem. + +### OpenvSwitch SDN Initialization + +OpenShift SDN initialization requires that the docker bridge be reconfigured and +docker is restarted. This complicates the situation when the node is running +within a container. When using the OVS SDN you'll see the node start, +reconfigure docker, restart docker which will restart all containers, and +finally start successfully. + +The node service may fail to start and be restarted a few times because the +master services are also restarted along with docker. We currently work around +this by relying on Restart=always in the docker based systemd units. -- cgit v1.2.3