diff --git a/doc/Pacemaker_Remote/en-US/Ch-Example.txt b/doc/Pacemaker_Remote/en-US/Ch-Example.txt index 33b70dfbb8..ca94044945 100644 --- a/doc/Pacemaker_Remote/en-US/Ch-Example.txt +++ b/doc/Pacemaker_Remote/en-US/Ch-Example.txt @@ -1,107 +1,107 @@ = Quick Example = If you already know how to use pacemaker, you'll likely be able to grasp this new concept of remote-nodes by reading through this quick example without having to sort through all the detailed walk-through steps. Here are the key configuration ingredients that make this possible using libvirt and KVM virtual guests. These steps strip everything down to the very basics. == Mile High View of Configuration Steps == * +Put an authkey with this path, /etc/pacemaker/authkey, on every cluster-node and virtual machine+. This secures remote communication and authentication. Run this command if you want to make a somewhat random authkey. [source,C] ---- dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1 ---- * +Install pacemaker_remote packages every virtual machine, enable pacemaker_remote on startup, and poke hole in firewall for tcp port 3121.+ [source,C] ---- yum install pacemaker-remote resource-agents systemctl enable pacemaker_remote # If you just want to see this work, disable iptables and ip6tables on most distros. # You may have to put selinux in permissive mode as well for the time being. firewall-cmd --add-port 3121/tcp --permanent ---- * +Give each virtual machine a static network address and unique hostname+ * +Tell pacemaker to launch a virtual machine and that the virtual machine is a remote-node capable of running resources by using the "remote-node" meta-attribute.+ with pcs [source,C] ---- # pcs resource create vm-guest1 VirtualDomain hypervisor="qemu:///system" config="vm-guest1.xml" meta +remote-node=guest1+ ---- raw xml [source,XML] ---- ---- In the example above the meta-attribute 'remote-node=guest1' tells pacemaker that this resource is a remote-node with the hostname 'guest1' that is capable of being integrated into the cluster. The cluster will attempt to contact the virtual machine's pacemaker_remote service at the hostname 'guest1' after it launches. == What those steps just did == Those steps just told pacemaker to launch a virtual machine called vm-guest1 and integrate that virtual machine as a remote-node called 'guest1'. Example crm_mon output after guest1 is integrated into cluster. [source,C] ---- Last updated: Wed Mar 13 13:52:39 2013 Last change: Wed Mar 13 13:25:17 2013 via crmd on node1 Stack: corosync Current DC: node1 (24815808) - partition with quorum -Version: 1.1.9 +Version: 1.1.10 2 Nodes configured, unknown expected votes 2 Resources configured. Online: [ node1 guest1] vm-guest1 (ocf::heartbeat:VirtualDomain): Started node1 ---- Now, you could place a resource, such as a webserver on guest1. [source,C] ---- # pcs resource create webserver apache params configfile=/etc/httpd/conf/httpd.conf op monitor interval=30s # pcs constraint webserver prefers guest1 ---- Now the crm_mon output would show a webserver launched on the guest1 remote-node. [source,C] ---- Last updated: Wed Mar 13 13:52:39 2013 Last change: Wed Mar 13 13:25:17 2013 via crmd on node1 Stack: corosync Current DC: node1 (24815808) - partition with quorum -Version: 1.1.9 +Version: 1.1.10 2 Nodes configured, unknown expected votes 2 Resources configured. Online: [ node1 guest1] vm-guest1 (ocf::heartbeat:VirtualDomain): Started node1 webserver (ocf::heartbeat::apache): Started guest1 ---- == Accessing Cluster from Remote-node == It is worth noting that after 'guest1' is integrated into the cluster, all the pacemaker cli tools immediately become available to the remote node. This means things like crm_mon, crm_resource, and crm_attribute will work natively on the remote-node as long as the connection between the remote-node and cluster-node exists. This is particularly important for any master/slave resources executing on the remote-node that need access to crm_master to set the nodes transient attributes. diff --git a/doc/Pacemaker_Remote/en-US/Ch-Intro.txt b/doc/Pacemaker_Remote/en-US/Ch-Intro.txt index a9d575a054..a505ea1916 100644 --- a/doc/Pacemaker_Remote/en-US/Ch-Intro.txt +++ b/doc/Pacemaker_Remote/en-US/Ch-Intro.txt @@ -1,55 +1,55 @@ = Extending High Availability Cluster into Virtual Nodes = == Overview == -The recent addition of the +pacemaker_remote+ service supported by +Pacemaker version 1.1.9.1 and greater+ allows nodes not running the cluster stack (pacemaker+corosync) to integrate into the cluster and have the cluster manage their resources just as if they were a real cluster node. This means that pacemaker clusters are now capable of managing both launching virtual environments (KVM/LXC) as well as launching the resources that live withing those virtual environments without requiring the virtual environments to run pacemaker or corosync. +The recent addition of the +pacemaker_remote+ service supported by +Pacemaker version 1.1.10 and greater+ allows nodes not running the cluster stack (pacemaker+corosync) to integrate into the cluster and have the cluster manage their resources just as if they were a real cluster node. This means that pacemaker clusters are now capable of managing both launching virtual environments (KVM/LXC) as well as launching the resources that live withing those virtual environments without requiring the virtual environments to run pacemaker or corosync. == Terms == +cluster-node+ - A baremetal hardware node running the High Availability stack (pacemaker + corosync) +remote-node+ - A virtual guest node running the pacemaker_remote service. +pacemaker_remote+ - A service daemon capable of performing remote application management within virtual guests (kvm and lxc) in both pacemaker cluster environments and standalone (non-cluster) environments. This service is an enhanced version of pacemaker's local resource manage daemon (LRMD) that is capable of managing and monitoring LSB, OCF, upstart, and systemd resources on a guest remotely. It also allows for most of pacemaker's cli tools (crm_mon, crm_resource, crm_master, crm_attribute, ect..) to work natively on remote-nodes. +LXC+ - A Linux Container defined by the libvirt-lxc Linux container driver. http://libvirt.org/drvlxc.html == Virtual Machine Use Case == The use of pacemaker_remote in virtual machines solves a deployment scenario that has traditionally been difficult to solve. +"I want a pacemaker cluster to manage virtual machine resources, but I also want pacemaker to be able to manage the resources that live within those virtual machines."+ In the past, users desiring this deployment had to make a decision. They would either have to sacrifice the ability of monitoring resources residing within virtual guests by running the cluster stack on the baremetal nodes, or run another cluster instance on the virtual guests where they potentially run into corosync scalability issues. There is a third scenario where the virtual guests run the cluster stack and join the same network as the baremetal nodes, but that can quickly hit issues with scalability as well. With the pacemaker_remote service we have a new option. * The baremetal cluster-nodes run the cluster stack (paceamaker+corosync). * The virtual remote-nodes run the pacemaker_remote service (nearly zero configuration required on the virtual machine side) * The cluster stack on the cluster-nodes launch the virtual machines and immediately connect to the pacemaker_remote service, allowing the virtual machines to integrate into the cluster just as if they were a real cluster-node. The key difference here between the virtual machine remote-nodes and the cluster-nodes is that the remote-nodes are not running the cluster stack. This means the remote nodes will never become the DC, and they do not take place in quorum. On the hand this also means that the remote-nodes are not bound to the scalability limits associated with the cluster stack either. +No 16 node corosync member limits+ to deal with. That isn't to say remote-nodes can scale indefinitely, but the expectation is that remote-nodes scale horizontally much further than cluster-nodes. Other than the quorum limitation, these remote-nodes behave just like cluster nodes in respects to resource management. The cluster is fully capable of managing and monitoring resources on each remote-node. You can build constraints against remote-nodes, put them in standby, or whatever else you'd expect to be able to do with normal cluster-nodes. They even show up in the crm_mon output as you would expect cluster-nodes to. To solidify the concept, an example cluster deployment integrating remote-nodes could look like this. * 16 cluster-nodes running corosync+pacemaker stack. * 64 pacemaker managed virtual machine resources running pacemaker_remote configured as remote-nodes. * 64 pacemaker managed webserver and database resources configured to run on the 64 remote-nodes. With this deployment you would have 64 webservers and databases running on 64 virtual machines on 16 hardware nodes all of which are managed and monitored by the same pacemaker deployment. == Linux Container Use Case == +I want to isolate and limit the system resources (cpu, memory, filesystem) a cluster resource can consume without using virtual machines.+ Using pacemaker_remote with Linux containers (libvirt-lxc) opens up some interesting possibilities for isolating resources in the cluster without the use of a hypervisor. We now have the ability to both define a contained environment with cpu and memory utilization limits and then assign resources to that contained environment all managed from within pacemaker. The LXC Walk-through section of this document outlines how pacemaker_remote can be used to bring Linux containers into the cluster as remote-nodes capable of executing resources. == Expanding the Cluster Stack == === Traditional HA Stack === image::images/pcmk-ha-cluster-stack.png["The Traditional Pacemaker Corosync HA Stack.",width="17cm",height="9cm",align="center"] === Remote-Node Enabled HA Stack === The stack grows one additional layer vertical so we can go further horizontal. image::images/pcmk-ha-remote-stack.png["Placing Pacemaker Remote into the Traditional HA Stack.",width="20cm",height="10cm",align="center"] diff --git a/doc/Pacemaker_Remote/en-US/Ch-KVM-Tutorial.txt b/doc/Pacemaker_Remote/en-US/Ch-KVM-Tutorial.txt index a57d7d73f1..fe0077524f 100644 --- a/doc/Pacemaker_Remote/en-US/Ch-KVM-Tutorial.txt +++ b/doc/Pacemaker_Remote/en-US/Ch-KVM-Tutorial.txt @@ -1,483 +1,483 @@ = KVM Walk-through = +What this tutorial is:+ This tutorial is an in-depth walk-through of how to get pacemaker to manage a KVM guest instance and integrate that guest into the cluster as a remote-node. +What this tutorial is not:+ This tutorial is not a realistic deployment scenario. The steps shown here are meant to get users familiar with the concept of remote-nodes as quickly as possible. == Step 1: Setup the Host == -This tutorial was created using Fedora 18 on the host and guest nodes. Anything that is capable of running libvirt and pacemaker v1.1.9.1 or greater will do though. An installation guide for installing Fedora 18 can be found here, http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/. +This tutorial was created using Fedora 18 on the host and guest nodes. Anything that is capable of running libvirt and pacemaker v1.1.10 or greater will do though. An installation guide for installing Fedora 18 can be found here, http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/. Fedora 18 (or similar distro) host preparation steps. === SElinux and Firewall === In order to simply this tutorial we will disable the selinux and the firewall on the host. +WARNING:+ These actions will open a significant security threat to machines exposed to the outside world. [source,C] ---- # setenforce 0 # sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config # systemctl disable iptables.service # systemctl disable ip6tables.service # rm '/etc/systemd/system/basic.target.wants/iptables.service' # rm '/etc/systemd/system/basic.target.wants/ip6tables.service' # systemctl stop iptables.service # systemctl stop ip6tables.service ---- === Install Cluster Software === [source,C] ---- # yum install -y pacemaker corosync pcs resource-agents ---- === Setup Corosync === Running the command below will attempt to detect the network address corosync should bind to. [source,C] ---- # export corosync_addr=`ip addr | grep "inet " | tail -n 1 | awk '{print $4}' | sed s/255/0/g` ---- Display and verify that address is correct [source,C] ---- # echo $corosync_addr ---- In many cases the address will be 192.168.1.0 if you are behind a standard home router. Now copy over the example corosync.conf. This code will inject your bindaddress and enable the vote quorum api which is required by pacemaker. [source,C] ---- # cp /etc/corosync/corosync.conf.example /etc/corosync/corosync.conf # sed -i.bak "s/.*\tbindnetaddr:.*/bindnetaddr:\ $corosync_addr/g" /etc/corosync/corosync.conf # cat << END >> /etc/corosync/corosync.conf quorum { provider: corosync_votequorum expected_votes: 2 } END ---- === Verify Cluster Software === Start the cluster [source,C] ---- # pcs cluster start ---- Verify corosync membership [source,C] ---- # pcs status corosync Membership information Nodeid Votes Name 1795270848 1 example-host (local) ---- Verify pacemaker status. At first the 'pcs cluster status' output will look like this. [source,C] ---- # pcs status Last updated: Thu Mar 14 12:26:00 2013 Last change: Thu Mar 14 12:25:55 2013 via crmd on example-host Stack: corosync Current DC: - Version: 1.1.9.1 + Version: 1.1.10 1 Nodes configured, unknown expected votes 0 Resources configured. ---- After about a minute you should see your host as a single node in the cluster. [source,C] ---- # pcs status Last updated: Thu Mar 14 12:28:23 2013 Last change: Thu Mar 14 12:25:55 2013 via crmd on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum Version: 1.1.8-9b13ea1 1 Nodes configured, unknown expected votes 0 Resources configured. Online: [ example-host ] ---- Go ahead and stop the cluster for now after verifying everything is in order. [source,C] ---- # pcs cluster stop ---- === Install Virtualization Software === [source,C] ---- # yum install -y kvm libvirt qemu-system qemu-kvm bridge-utils virt-manager # systemctl enable libvirtd.service ---- reboot the host == Step2: Create the KVM guest == I am not going to outline the installation steps required to create a kvm guest. There are plenty of tutorials available elsewhere that do that. I recommend using a Fedora 18 or greater distro as your guest as that is what I am testing this tutorial with. === Setup Guest Network === Run the commands below to set up a static ip address (192.168.122.10) and hostname (guest1). [source,C] ---- export remote_hostname=guest1 export remote_ip=192.168.122.10 export remote_gateway=192.168.122.1 yum remove -y NetworkManager rm -f /etc/hostname cat << END >> /etc/hostname $remote_hostname END hostname $remote_hostname cat << END >> /etc/sysconfig/network HOSTNAME=$remote_hostname GATEWAY=$remote_gateway END sed -i.bak "s/.*BOOTPROTO=.*/BOOTPROTO=none/g" /etc/sysconfig/network-scripts/ifcfg-eth0 cat << END >> /etc/sysconfig/network-scripts/ifcfg-eth0 IPADDR0=$remote_ip PREFIX0=24 GATEWAY0=$remote_gateway DNS1=$remote_gateway END systemctl restart network systemctl enable network.service systemctl enable sshd systemctl start sshd echo "checking connectivity" ping www.google.com ---- To simplify the tutorial we'll go ahead and disable selinux on the guest. We'll also need to poke a hole through the firewall on port 3121 (the default port for pacemaker_remote) so the host can contact the guest. [source,C] ---- # setenforce 0 # sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config # firewall-cmd --add-port 3121/tcp --permanent ---- If you still encounter connection issues just disable iptables and ipv6tables on the guest like we did on the host to guarantee you'll be able to contact the guest from the host. At this point you should be able to ssh into the guest from the host. === Setup Pacemaker Remote === On the +HOST+ machine run these commands to generate an authkey and copy it to the /etc/pacemaker folder on both the host and guest. [source,C] ---- # mkdir /etc/pacemaker # dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1 # scp -r /etc/pacemaker root@192.168.122.10:/etc/ ---- Now on the +GUEST+ install pacemaker-remote package and enable the daemon to run at startup. In the commands below you will notice the 'pacemaker' and 'pacemaker_remote' packages are being installed. The 'pacemaker' package is not required. The only reason it is being installed for this tutorial is because it contains the a 'Dummy' resource agent we will be using later on to test the remote-node. [source,C] ---- # yum install -y pacemaker paceamaker-remote resource-agents # systemctl enable pacemaker_remote.service ---- Now start pacemaker_remote on the guest and verify the start was successful. [source,C] ---- # systemctl start pacemaker_remote.service # systemctl status pacemaker_remote pacemaker_remote.service - Pacemaker Remote Service Loaded: loaded (/usr/lib/systemd/system/pacemaker_remote.service; enabled) Active: active (running) since Thu 2013-03-14 18:24:04 EDT; 2min 8s ago Main PID: 1233 (pacemaker_remot) CGroup: name=systemd:/system/pacemaker_remote.service └─1233 /usr/sbin/pacemaker_remoted Mar 14 18:24:04 guest1 systemd[1]: Starting Pacemaker Remote Service... Mar 14 18:24:04 guest1 systemd[1]: Started Pacemaker Remote Service. Mar 14 18:24:04 guest1 pacemaker_remoted[1233]: notice: lrmd_init_remote_tls_server: Starting a tls listener on port 3121. ---- === Verify Host Connection to Guest === Before moving forward it's worth going ahead and verifying the host can contact the guest on port 3121. Here's a trick you can use. Connect using telnet from the host. The connection will get destroyed, but how it is destroyed tells you whether it worked or not. First add guest1 to the host machine's /etc/hosts file if you haven't already. This is required unless you have dns setup in a way where guest1's address can be discovered. [source,C] ---- # cat << END >> /etc/hosts 192.168.122.10 guest1 END ---- If running the telnet command on the host results in this output before disconnecting, the connection works. [source,C] ---- # telnet guest1 3121 Trying 192.168.122.10... Connected to guest1. Escape character is '^]'. Connection closed by foreign host. ---- If you see this, the connection is not working. [source,C] ---- # telnet guest1 3121 Trying 192.168.122.10... telnet: connect to address 192.168.122.10: No route to host ---- Once you can successfully connect to the guest from the host, shutdown the guest. Pacemaker will be managing the virtual machine from this point forward. == Step3: Integrate KVM guest into Cluster. == Now the fun part, integrating the virtual machine you've just created into the cluster. It is incredibly simple. === Start the Cluster === On the host, start pacemaker. [source,C] ---- # pcs cluster start ---- Wait for the host to become the DC. The output of 'pcs status' should look similar to this after about a minute. [source,C] ---- Last updated: Thu Mar 14 16:41:22 2013 Last change: Thu Mar 14 16:41:08 2013 via crmd on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 1 Nodes configured, unknown expected votes 0 Resources configured. Online: [ example-host ] ---- Now enable the cluster to work without quorum or stonith. This is required just for the sake of getting this tutorial to work with a single cluster-node. [source,C] ---- # pcs property set stonith-enabled=false # pcs property set no-quorum-policy=ignore ---- === Integrate KVM Guest as remote-node === If you didn't already do this earlier in the verify host to guest connection section, add the KVM guest's ip to the host's /etc/hosts file so we can connect by hostname. The command below will do that if you used the same ip address I used earlier. [source,C] ---- # cat << END >> /etc/hosts 192.168.122.10 guest1 END ---- We will use the +VirtualDomain+ resource agent for the management of the virtual machine. This agent requires the virtual machine's xml config to be dumped to a file on disk. To do this pick out the name of the virtual machine you just created from the output of this list. [source,C] ---- # virsh list --all Id Name State ______________________________________________ - guest1 shut off ---- In my case I named it guest1. Dump the xml to a file somewhere on the host using the following command. [source,C] ---- # virsh dumpxml guest1 > /root/guest1.xml ---- Now just register the resource with pacemaker and you're set! [source,C] ---- # pcs resource create vm-guest1 VirtualDomain hypervisor="qemu:///system" config="/root/guest1.xml" meta remote-node=guest1 ---- Once the 'vm-guest1' resource is started you will see 'guest1' appear in the 'pcs status' output as a node. The final 'pcs status' output should look something like this. [source,C] ---- Last updated: Fri Mar 15 09:30:30 2013 Last change: Thu Mar 14 17:21:35 2013 via cibadmin on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 2 Nodes configured, unknown expected votes 2 Resources configured. Online: [ example-host guest1 ] Full list of resources: vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host ---- === Starting Resources on KVM Guest === The commands below demonstrate how resources can be executed on both the remote-node and the cluster-node. Create a few Dummy resources. Dummy resources are real resource agents used just for testing purposes. They actually execute on the host they are assigned to just like an apache server or database would, except their execution just means a file was created. When the resource is stopped, that the file it created is removed. [source,C] ---- # pcs resource create FAKE1 ocf:pacemaker:Dummy # pcs resource create FAKE2 ocf:pacemaker:Dummy # pcs resource create FAKE3 ocf:pacemaker:Dummy # pcs resource create FAKE4 ocf:pacemaker:Dummy # pcs resource create FAKE5 ocf:pacemaker:Dummy ---- Now check your 'pcs status' output. In the resource section you should see something like the following, where some of the resources got started on the cluster-node, and some started on the remote-node. [source,C] ---- Full list of resources: vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host FAKE1 (ocf::pacemaker:Dummy): Started guest1 FAKE2 (ocf::pacemaker:Dummy): Started guest1 FAKE3 (ocf::pacemaker:Dummy): Started example-host FAKE4 (ocf::pacemaker:Dummy): Started guest1 FAKE5 (ocf::pacemaker:Dummy): Started example-host ---- The remote-node, 'guest1', reacts just like any other node in the cluster. For example, pick out a resource that is running on your cluster-node. For my purposes I am picking FAKE3 from the output above. We can force FAKE3 to run on 'guest1' in the exact same way we would any other node. [source,C] ---- # pcs constraint FAKE3 prefers guest1 ---- Now looking at the bottom of the 'pcs status' output you'll see FAKE3 is on 'guest1'. [source,C] ---- Full list of resources: vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host FAKE1 (ocf::pacemaker:Dummy): Started guest1 FAKE2 (ocf::pacemaker:Dummy): Started guest1 FAKE3 (ocf::pacemaker:Dummy): Started guest1 FAKE4 (ocf::pacemaker:Dummy): Started example-host FAKE5 (ocf::pacemaker:Dummy): Started example-host ---- === Testing Remote-node Recovery and Fencing === Pacemaker's policy engine is smart enough to know fencing remote-nodes associated with a virtual machine means shutting off/rebooting the virtual machine. No special configuration is necessary to make this happen. If you are interested in testing this functionality out, trying stopping the guest's pacemaker_remote daemon. This would be equivalent of abruptly terminating a cluster-node's corosync membership without properly shutting it down. ssh into the guest and run this command. [source,C] ---- # kill -9 `pidof pacemaker_remoted` ---- After a few seconds or so you'll see this in your 'pcs status' output. The 'guest1' node will be show as offline as it is being recovered. [source,C] ---- Last updated: Fri Mar 15 11:00:31 2013 Last change: Fri Mar 15 09:54:16 2013 via cibadmin on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 2 Nodes configured, unknown expected votes 7 Resources configured. Online: [ example-host ] OFFLINE: [ guest1 ] Full list of resources: vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host FAKE1 (ocf::pacemaker:Dummy): Stopped FAKE2 (ocf::pacemaker:Dummy): Stopped FAKE3 (ocf::pacemaker:Dummy): Stopped FAKE4 (ocf::pacemaker:Dummy): Started example-host FAKE5 (ocf::pacemaker:Dummy): Started example-host Failed actions: guest1_monitor_30000 (node=example-host, call=3, rc=7, status=complete): not running ---- Once recovery of the guest is complete, you'll see it automatically get re-integrated into the cluster. The final 'pcs status' output should look something like this. [source,C] ---- Last updated: Fri Mar 15 11:03:17 2013 Last change: Fri Mar 15 09:54:16 2013 via cibadmin on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 2 Nodes configured, unknown expected votes 7 Resources configured. Online: [ example-host guest1 ] Full list of resources: vm-guest1 (ocf::heartbeat:VirtualDomain): Started example-host FAKE1 (ocf::pacemaker:Dummy): Started guest1 FAKE2 (ocf::pacemaker:Dummy): Started guest1 FAKE3 (ocf::pacemaker:Dummy): Started guest1 FAKE4 (ocf::pacemaker:Dummy): Started example-host FAKE5 (ocf::pacemaker:Dummy): Started example-host Failed actions: guest1_monitor_30000 (node=example-host, call=3, rc=7, status=complete): not running ---- === Accessing Cluster Tools from Remote-node === Besides just allowing the cluster to manage resources on a remote-node, pacemaker_remote has one other trick. +The pacemaker_remote daemon allows nearly all the pacemaker tools (crm_resource, crm_mon, crm_attribute, crm_master) to work on remote nodes natively.+ Try it, run +crm_mon+ or +pcs status+ on the guest after pacemaker has integrated the remote-node into the cluster. These tools just work. These means resource agents such as master/slave resources which need access to tools like crm_master work seamlessly on the remote-nodes. diff --git a/doc/Pacemaker_Remote/en-US/Ch-LXC-Tutorial.txt b/doc/Pacemaker_Remote/en-US/Ch-LXC-Tutorial.txt index bcb1c3cc48..c3459c086a 100644 --- a/doc/Pacemaker_Remote/en-US/Ch-LXC-Tutorial.txt +++ b/doc/Pacemaker_Remote/en-US/Ch-LXC-Tutorial.txt @@ -1,328 +1,328 @@ = Linux Container (LXC) Walk-through = +What this tutorial is:+ This tutorial demonstrates how pacemaker_remote can be used with Linux containers (managed by libvirt-lxc) to run cluster resources in an isolated environment. +What this tutorial is not:+ This tutorial is not a realistic deployment scenario. The steps shown here are meant to introduce users to the concept of managing Linux container environments with Pacemaker. == Step 1: Setup LXC Host == -This tutorial was tested with Fedora 18. Anything that is capable of running libvirt and pacemaker v1.1.9.1 or greater will do though. An installation guide for installing Fedora 18 can be found here, http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/. +This tutorial was tested with Fedora 18. Anything that is capable of running libvirt and pacemaker v1.1.10 or greater will do though. An installation guide for installing Fedora 18 can be found here, http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/. Fedora 18 (or similar distro) host preparation steps. === SElinux and Firewall Rules === In order to simply this tutorial we will disable the selinux and the firewall on the host. WARNING: These actions pose a significant security issues to machines exposed to the outside world. Basically, just don't do this on your production system. [source,C] ---- # setenforce 0 # sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config # firewall-cmd --add-port 3121/tcp --permanent # systemctl disable iptables.service # systemctl disable ip6tables.service # rm '/etc/systemd/system/basic.target.wants/iptables.service' # rm '/etc/systemd/system/basic.target.wants/ip6tables.service' # systemctl stop iptables.service # systemctl stop ip6tables.service ---- === Install Cluster Software on Host === [source,C] ---- # yum install -y pacemaker pacemaker-remote corosync pcs resource-agents ---- === Configure Corosync === Running the command below will attempt to detect the network address corosync should bind to. [source,C] ---- # export corosync_addr=`ip addr | grep "inet " | tail -n 1 | awk '{print $4}' | sed s/255/0/g` ---- Display and verify the address is correct [source,C] ---- # echo $corosync_addr ---- In most cases the address will be 192.168.1.0 if you are behind a standard home router. Now copy over the example corosync.conf. This code will inject your bindaddress and enable the vote quorum api which is required by pacemaker. [source,C] ---- # cp /etc/corosync/corosync.conf.example /etc/corosync/corosync.conf # sed -i.bak "s/.*\tbindnetaddr:.*/bindnetaddr:\ $corosync_addr/g" /etc/corosync/corosync.conf # cat << END >> /etc/corosync/corosync.conf quorum { provider: corosync_votequorum expected_votes: 2 } END ---- === Verify Cluster === Start the cluster [source,C] ---- # pcs cluster start ---- Verify corosync membership [source,C] ---- # pcs status corosync Membership information Nodeid Votes Name 1795270848 1 example-host (local) ---- Verify pacemaker status. At first the 'pcs cluster status' output will look like this. [source,C] ---- # pcs status Last updated: Thu Mar 14 12:26:00 2013 Last change: Thu Mar 14 12:25:55 2013 via crmd on example-host Stack: corosync Current DC: - Version: 1.1.9.1 + Version: 1.1.10 1 Nodes configured, unknown expected votes 0 Resources configured. ---- After about a minute you should see your host as a single node in the cluster. [source,C] ---- # pcs status Last updated: Thu Mar 14 12:28:23 2013 Last change: Thu Mar 14 12:25:55 2013 via crmd on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum Version: 1.1.8-9b13ea1 1 Nodes configured, unknown expected votes 0 Resources configured. Online: [ example-host ] ---- Go ahead and stop the cluster for now after verifying everything is in order. [source,C] ---- # pcs cluster stop ---- == Step 2: Setup LXC Environment == === Install Libvirt LXC software === [source,C] ---- # yum install -y libvirt libvirt-daemon-lxc wget # systemctl enable libvirtd ---- At this point, restart the host. === Generate Libvirt LXC domains === I've attempted to simply this tutorial by creating a script to auto generate the libvirt-lxc xml domain definitions. Download the script to whatever directory you want the containers to live in. In this example I am using the /root/lxc/ directory. [source,C] ---- # mkdir /root/lxc/ # cd /root/lxc/ # wget https://raw.github.com/davidvossel/pcmk-lxc-autogen/master/lxc-autogen # chmod 755 lxc-autogen ---- Now execute the script. [source,C] ---- # ./lxc-autogen ---- After executing the script you will see a bunch of directories and xml files are generated. Those xml files are the libvirt-lxc domain definitions, and the directories are used as some special mount points for each container. If you open up one of the xml files you'll be able to see how the cpu, memory, and filesystem resources for the container are defined. You can use the libvirt-lxc driver's documentation found here, http://libvirt.org/drvlxc.html, as a reference to help understand all the parts of the xml file. The lxc-autogen script is not complicated and is worth exploring in order to grasp how the environment is generated. It is worth noting that this environment is dependent on use of libvirt's default network interface. Verify the commands below look the same as your environment. The default network address 192.168.122.1 should have been generated by automatically when you installed the virtualization software. [source,C] ---- # virsh net-list Name State Autostart Persistent ________________________________________________________ default active yes yes # virsh net-dumpxml default | grep -e "ip address=" ---- === Generate the Authkey === Generate the authkey used to secure connections between the host and the lxc guest pacemaker_remote instances. This is sort of a funny case because the lxc guests and the host will share the same key file in the /etc/pacemaker/ directory. If in a different deployment where the lxc guests do not share the host's /etc/pacemaker directory, this key will have to be copied into each lxc guest. [source,C] ---- # dd if=/dev/urandom of=/etc/pacemaker/authkey bs=4096 count=1 ---- == Step 3: Integrate LXC guests into Cluster. == === Start Cluster === On the host, start pacemaker. [source,C] ---- # pcs cluster start ---- Wait for the host to become the DC. The output of 'pcs status' should look similar to this after about a minute. [source,C] ---- Last updated: Thu Mar 14 16:41:22 2013 Last change: Thu Mar 14 16:41:08 2013 via crmd on example-host Stack: corosync Current DC: example-host (1795270848) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 1 Nodes configured, unknown expected votes 0 Resources configured. Online: [ example-host ] ---- Now enable the cluster to work without quorum or stonith. This is required just for the sake of getting this tutorial to work with a single cluster-node. [source,C] ---- # pcs property set stonith-enabled=false # pcs property set no-quorum-policy=ignore ---- === Integrate LXC Guests as remote-nodes === If you ran the 'lxc-autogen' script with default parameters, 3 lxc domain definitions were created as .xml files. If you used the same directory I used for the lxc environment, the config files will be located in /root/lxc. Replace the 'config' parameters in the following pcs commands if yours should be different. The pcs commands below each configure a lxc guest as a remote-node in pacemaker. Behind the scenes each lxc guest is launching an instance of pacemaker_remote allowing pacemaker to integrate the lxc guests as remote-nodes. The meta-attribute 'remote-node=' used in each command is what tells pacemaker that the lxc guest is both a resource and a remote-node capable of running resources. In this case, the 'remote-node' attribute also indicates to pacemaker that it can contact each lxc's pacemaker_remote service by using the remote-node name as the hostname. If you look in the /etc/hosts/ file you will see entries for each lxc guest. These entries were auto-generated earlier by the 'lxc-autogen' script. [source,C] ---- # pcs resource create container1 VirtualDomain force_stop="true" hypervisor="lxc:///" config="/root/lxc/lxc1.xml" meta remote-node=lxc1 # pcs resource create container2 VirtualDomain force_stop="true" hypervisor="lxc:///" config="/root/lxc/lxc2.xml" meta remote-node=lxc2 # pcs resource create container3 VirtualDomain force_stop="true" hypervisor="lxc:///" config="/root/lxc/lxc3.xml" meta remote-node=lxc3 ---- After creating the container resources you 'pcs status' should look like this. [source,C] ---- Last updated: Mon Mar 18 17:15:46 2013 Last change: Mon Mar 18 17:15:26 2013 via cibadmin on guest1 Stack: corosync Current DC: example-host (175810752) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 4 Nodes configured, unknown expected votes 6 Resources configured. Online: [ example-host lxc1 lxc2 lxc3 ] Full list of resources: container3 (ocf::heartbeat:VirtualDomain): Started example-host container1 (ocf::heartbeat:VirtualDomain): Started example-host container2 (ocf::heartbeat:VirtualDomain): Started example-host ---- === Starting Resources on LXC Guests === Now that the lxc guests are integrated into the cluster, lets generate some Dummy resources to run on them. Dummy resources are real resource agents used just for testing purposes. They actually execute on the node they are assigned to just like an apache server or database would, except their execution just means a file was created. When the resource is stopped, that the file it created is removed. [source,C] ---- # pcs resource create FAKE1 ocf:pacemaker:Dummy # pcs resource create FAKE2 ocf:pacemaker:Dummy # pcs resource create FAKE3 ocf:pacemaker:Dummy # pcs resource create FAKE4 ocf:pacemaker:Dummy # pcs resource create FAKE5 ocf:pacemaker:Dummy ---- After creating the Dummy resources you will see that the resource got distributed among all the nodes. The 'pcs status' output should look similar to this. [source,C] ---- Last updated: Mon Mar 18 17:31:54 2013 Last change: Mon Mar 18 17:31:05 2013 via cibadmin on example-host Stack: corosync Current DC: example=host (175810752) - partition WITHOUT quorum -Version: 1.1.9.1 +Version: 1.1.10 4 Nodes configured, unknown expected votes 11 Resources configured. Online: [ example-host lxc1 lxc2 lxc3 ] Full list of resources: container3 (ocf::heartbeat:VirtualDomain): Started example-host container1 (ocf::heartbeat:VirtualDomain): Started example-host container2 (ocf::heartbeat:VirtualDomain): Started example-host FAKE1 (ocf::pacemaker:Dummy): Started lxc1 FAKE2 (ocf::pacemaker:Dummy): Started lxc2 FAKE3 (ocf::pacemaker:Dummy): Started lxc3 FAKE4 (ocf::pacemaker:Dummy): Started lxc1 FAKE5 (ocf::pacemaker:Dummy): Started lxc2 ---- To witness that Dummy agents are running within the lxc guests browse one of the lxc domain's filesystem folders. Each lxc guest has a custom mount point for the '/var/run/'directory, which is the location the Dummy resources write their state files to. [source,C] ---- # ls lxc1-filesystem/var/run/ Dummy-FAKE4.state Dummy-FAKE.state ---- If you are curious, take a look at lxc1.xml to see how the filesystem is mounted. === Testing LXC Guest Failure === You will be able to see each pacemaker_remoted process running in each lxc guest from the host machine. [source,C] ---- # ps -A | grep -e pacemaker_remote* 9142 pts/2 00:00:00 pacemaker_remot 10148 pts/4 00:00:00 pacemaker_remot 10942 pts/6 00:00:00 pacemaker_remot ---- In order to see how the cluster reacts to a failed lxc guest. Try killing one of the pacemaker_remote instances. [source,C] ---- # kill -9 9142 ---- After a few moments the lxc guest that was running that instance of pacemaker_remote will be recovered along with all the resources running within that container.