Rhel cluster basics 3
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Conga is a centralized tool for configuring and managing Red Hat clusters and storage through a web interface. It has three main components - luci server, ricci agents, and a database. Luci provides tools on different tabs for adding/removing systems, configuring clusters and storage. Command line tools like ccs_tool and clustat can also manage clusters. The Piranha Configuration Tool is a web GUI for configuring Linux Virtual Server load balancing through settings like interfaces, redundancy, and virtual servers.
Rhel cluster basics 3
- 2. Conga Conga is an integrated set of software components that provides centralized configuration and management of Red Hat clusters and storage.
- 3. Conga: Features • One Web interface for managing cluster and storage • Automated Deployment of Cluster Data and Supporting Packages • Easy Integration with Existing Clusters • No Need to Re-Authenticate • Integration of Cluster Status and Logs • Fine-Grained Control over User Permissions
- 4. Conga: Primary Components • The primary components in Conga are luci and ricci, which are separately installable. • luci is a server that runs on one computer and communicates with multiple clusters and computers via ricci. • ricci is an agent that runs on each computer (either a cluster member or a standalone computer) managed by Conga.
- 5. Luci luci is accessible through a Web browser and provides three major functions that are accessible through the following tabs: • homebase — Provides tools for adding and deleting computers, adding and deleting users, and configuring user privileges. Only a system administrator is allowed to access this tab. • cluster — Provides tools for creating and configuring clusters. Each instance of luci lists clusters that have been set up with that luci. A system administrator can administer all clusters listed on this tab. Other users can administer only clusters that the user has permission to manage (granted by an administrator). • storage — Provides tools for remote administration of storage. With the tools on this tab, you can manage storage on computers whether they belong to a cluster or not.
- 6. Luci • To administer a cluster or storage, an administrator adds (or registers) a cluster or a computer to a luci server. When a cluster or a computer is registered with luci, the FQDN hostname or IP address of each computer is stored in a luci database. • Each luci instance has one user at initial installation — admin. Only the admin user may add systems to a luci server. Also, the admin user can create additional user accounts and determine which users are allowed to access clusters and computers registered in the luci database.
- 10. Cluster Administration GUI • The system-config-cluster cluster administration graphical user interface (GUI) available with Red Hat Cluster Suite. • The GUI is for use with the cluster infrastructure and the high-availability service management components.
- 11. Cluster Administration GUI • The GUI consists of two major functions: – Cluster Configuration Tool – Cluster Status Tool • The Cluster Configuration Tool provides the capability to create, edit, and propagate the cluster configuration file (/etc/cluster/cluster.conf). • The Cluster Status Tool provides the capability to manage high-availability services.
- 13. Cluster Configuration Tool: components Cluster Nodes — Displays cluster nodes. Using configuration buttons you can add nodes, delete nodes, edit node properties, and configure fencing methods for each node. Fence Devices — Displays fence devices. Using configuration buttons you can add fence devices, delete fence devices, and edit fence-device properties. Fence devices must be defined before you can configure fencing (with the Manage Fencing For This Node button) for each node. Managed Resources — Displays failover domains, resources, and services.
- 14. Cluster Configuration Tool: components Managed Resources — Failover Domains — For configuring one or more subsets of cluster nodes used to run a high-availability service in the event of a node failure. Resources — For configuring shared resources to be used by high-availability services. Shared resources consist of file systems, IP addresses, NFS mounts and exports, and user- created scripts that are available to any high-availability service in the cluster. Services — For creating and configuring high-availability services. A service is configured by assigning resources (shared or private), assigning a failover domain, and defining a recovery policy for the service.
- 16. Command Line Administration Tools • In addition to Conga and the system-config- cluster Cluster Administration GUI, command line tools are available for administering the cluster infrastructure and the high-availability service management components. • The command line tools are used by the Cluster Administration GUI and init scripts supplied by Red Hat.
- 17. Command Line Tool Used With Purpose ccs_tool — Cluster Configuration System Tool Cluster Infrastructure ccs_tool is a program for making online updates to the cluster configuration file. It provides the capability to create and modify cluster infrastructure components (for example, creating a cluster, adding and removing a node). cman_tool — Cluster Management Tool Cluster Infrastructure cman_tool is a program that manages the CMAN cluster manager. It provides the capability to join a cluster, leave a cluster, kill a node, or change the expected quorum votes of a node in a cluster. fence_tool — Fence Tool Cluster Infrastructure fence_tool is a program used to join or leave the default fence domain. Specifically, it starts the fence daemon (fenced) to join the domain and kills fenced to leave the domain. Command Line Tools
- 18. Command Line Tool Used With Purpose clustat — Cluster Status Utility High-availability Service Management Components The clustat command displays the status of the cluster. It shows membership information, quorum view, and the state of all configured user services. clusvcadm — Cluster User Service Administration Utility High-availability Service Management Components The clusvcadm command allows you to enable, disable, relocate, and restart high-availability services in a cluster. Command Line Tools
- 19. Linux Virtual Server Administration GUI
- 20. Piranha Configuration Tool • The Piranha Configuration Tool is a Web-browser graphical user interface (GUI) that provides a structured approach to creating the configuration file for LVS — /etc/sysconfig/ha/lvs.cf. • To access the Piranha Configuration Tool you need the piranha-gui service running on the active LVS router. • You can access the Piranha Configuration Tool locally (URL: http://localhost:3636) or remotely (hostname or the real IP address :3636) with a Web browser. • If you are accessing the Piranha Configuration Tool remotely, you need an ssh connection to the active LVS router as the root user.
- 21. Piranha Configuration Tool: The Welcome panel
- 22. Piranha Configuration Tool: CONTROL/MONITORING
- 23. Piranha Configuration Tool: CONTROL/MONITORING Logging in to the welcome page provides access to the four main screens or panels: CONTROL/MONITORING, GLOBAL SETTINGS, REDUNDANCY, and VIRTUAL SERVERS. The CONTROL/MONITORING Panel displays runtime status. It displays the status of the pulse daemon, the LVS routing table, and the LVS-spawned nanny processes. Auto update Enables the status display to be updated automatically at a user-configurable interval set in the Update frequency in seconds text box (the default value is 10 seconds). Update information now Provides manual update of the status information. CHANGE PASSWORD Clicking this button takes you to a help screen with information on how to change the administrative password for the Piranha Configuration Tool.
- 24. Piranha Configuration Tool: GLOBAL SETTINGS The GLOBAL SETTINGS panel is where the LVS administrator defines the networking details for the primary LVS router's public and private network interfaces. The top half of this panel sets up the primary LVS router's public and private network interfaces. Primary server public IP The publicly routable real IP address for the primary LVS node. Primary server private IP The real IP address for an alternative network interface on the primary LVS node. This address is used solely as an alternative heartbeat channel for the backup router. Use network type Selects select NAT routing.
- 25. Piranha Configuration Tool: GLOBAL SETTINGS The next three fields are specifically for the NAT router's virtual network interface connected the private network with the real servers. NAT Router IP The private floating IP in this text field. This floating IP should be used as the gateway for the real servers. NAT Router netmask If the NAT router's floating IP needs a particular netmask, select it from drop-down list. NAT Router device Defines the device name of the network interface for the floating IP address, such as eth1:1.
- 26. Piranha Configuration Tool: GLOBAL SETTINGS
- 27. Piranha Configuration Tool: REDUNDANCY The REDUNDANCY panel allows you to configure of the backup LVS router node and set various heartbeat monitoring options. Redundant server public IP The public real IP address for the backup LVS router. Redundant server private IP The backup router's private real IP address. The rest of the panel is for configuring the heartbeat channel, which is used by the backup node to monitor the primary node for failure.
- 28. Piranha Configuration Tool: REDUNDANCY Heartbeat Interval (seconds) Sets the number of seconds between heartbeats — the interval that the backup node will check the functional status of the primary LVS node. Assume dead after (seconds) If the primary LVS node does not respond after this number of seconds, then the backup LVS router node will initiate failover. Heartbeat runs on port Sets the port at which the heartbeat communicates with the primary LVS node. The default is set to 539 if this field is left blank.
- 29. Piranha Configuration Tool: REDUNDANCY
- 30. Piranha Configuration Tool: REDUNDANCY Redundant server public IP : The public real IP address for the backup LVS router. Redundant server private IP : The backup router's private real IP address. The rest of the panel is for configuring the heartbeat channel, which is used by the backup node to monitor the primary node for failure. Heartbeat Interval (seconds) : Sets the number of seconds between heartbeats — the interval that the backup node will check the functional status of the primary LVS node.
- 31. Piranha Configuration Tool: REDUNDANCY Assume dead after (seconds) : If the primary LVS node does not respond after this number of seconds, then the backup LVS router node will initiate failover. Heartbeat runs on port : Sets the port at which the heartbeat communicates with the primary LVS node. The default is set to 539 if this field is left blank.
- 32. VIRTUAL SERVERS
- 33. VIRTUAL SERVERS Panel • Each server displayed in the VIRTUAL SERVERS panel can be configured on subsequent screens or subsections. • To add a service, click the ADD button. To remove a service, select it by clicking the radio button next to the virtual server and click the DELETE button. • To enable or disable a virtual server in the table click its radio button and click the (DE)ACTIVATE button. • After adding a virtual server, you can configure it by clicking the radio button to its left and clicking the EDIT button to display the VIRTUAL SERVER subsection.
- 35. VIRTUAL SERVERS Subsection • Name: A descriptive name to identify the virtual server. This name is not the hostname for the machine, so make it descriptive and easily identifiable. You can even reference the protocol used by the virtual server, such as HTTP. • Application port: The port number through which the service application will listen. • Protocol: Provides a choice of UDP or TCP, in a drop-down menu. • Virtual IP Address: The virtual server's floating IP address.
- 36. VIRTUAL SERVERS Subsection • Virtual IP: Network Mask The netmask for this virtual server, in the drop-down menu. • Firewall Mark: For entering a firewall mark integer value when bundling multi-port protocols or creating a multi-port virtual server for separate, but related protocols. • Device: The name of the network device to which you want the floating IP address defined in the Virtual IP Address field to bind. • Re-entry Time: An integer value that defines the number of seconds before the active LVS router attempts to use a real server after the real server failed.
- 37. VIRTUAL SERVERS Subsection • Service Timeout: An integer value that defines the number of seconds before a real server is considered dead and not available. • Quiesce server: When the Quiesce server radio button is selected, anytime a new real server node comes online, the least-connections table is reset to zero so the active LVS router routes requests as if all the real servers were freshly added to the cluster. This option prevents the a new server from becoming bogged down with a high number of connections upon entering the cluster.
- 38. VIRTUAL SERVERS Subsection • Load monitoring tool: The LVS router can monitor the load on the various real servers by using either rup or ruptime. If you select rup from the drop-down menu, each real server must run the rstatd service. If you select ruptime, each real server must run the rwhod service. • Scheduling: The preferred scheduling algorithm from the drop-down menu. The default is Weighted least- connection. • Persistence: Used if you need persistent connections to the virtual server during client transactions. Specifies the number of seconds of inactivity allowed to lapse before a connection times out in this text field. • Persistence Network Mask To limit persistence to particular subnet, select the appropriate network mask from the drop-down menu.
- 39. REAL SERVERS Subsection Click the ADD button to add a new server. To delete an existing server, select the radio button beside it and click the DELETE button. Click the EDIT button to load the EDIT REAL SERVER panel
- 40. REAL SERVERS Subsection Name A descriptive name for the real server. Address The real server's IP address. Weight An integer value indicating this host's capacity relative to that of other hosts in the pool.
- 41. EDIT MONITORING SCRIPTS Subsection
- 42. EDIT MONITORING SCRIPTS Subsection Sending Program: You can use this field to specify the path to a service- checking script. This function is especially helpful for services that require dynamically changing data, such as HTTPS or SSL. Send: A string for the nanny daemon to send to each real server in this field. By default the send field is completed for HTTP. If you leave this field blank, the nanny daemon attempts to open the port and assume the service is running if it succeeds. Only one send sequence is allowed in this field, and it can only contain printable, ASCII characters as well as the following escape characters: n for new line. r for carriage return. t for tab. to escape the next character which follows it. Expect: The textual response the server should return if it is functioning properly.