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High Availability

High Availability. Module 12. You Are Here. vSphere Environment. Operations. Introduction to VMware Virtualization. Access Control. VMware ESX and ESXi. Resource Monitoring. VMware vCenter Server. Data Protection. Networking. Scalability. High Availability. Storage. Virtual Machines.

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High Availability

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  1. High Availability Module 12

  2. You Are Here vSphere Environment Operations Introduction to VMware Virtualization Access Control VMware ESX and ESXi Resource Monitoring VMware vCenter Server Data Protection Networking Scalability High Availability Storage Virtual Machines Patch Management Installing VMware ESX and ESXi VMware vSphere 4.1: Install, Configure, Manage – Revision A

  3. Importance • Most organizations rely on computer-based services like email, databases, and Web-based applications. The failure of any of these services can mean lost productivity and revenue. Configuring highly available, computer-based services is extremely important for an organization to remain competitive in contemporary business environments. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  4. Module Lessons • Lesson 1: High Availability • Lesson 2: Managing VMware HA • Lesson 3: FT VMware vSphere 4.1: Install, Configure, Manage – Revision A

  5. Lesson 1:High Availability VMware vSphere 4.1: Install, Configure, Manage – Revision A

  6. Lesson Objectives • Describe VMware® solutions for: • High availability • Fault tolerance • Configure a VMware High Availability cluster VMware vSphere 4.1: Install, Configure, Manage – Revision A

  7. High Availability and Fault Tolerance A highly available system is one that is continuously operational for a desirably long length of time. A fault-tolerant system is designed so that, in the event of an unplanned outage, a backup component can immediately take over with no loss of service. What level of virtual machine availability is important to you? VMware vSphere 4.1: Install, Configure, Manage – Revision A

  8. VMware Availability and Fault Tolerance Solutions Availability features in VMware vSphere™: • Storage availability using multipathing • Network availability using network interface card (NIC) teaming • VMware vMotion™ and Storage vMotion • VMware HA • VMware Fault Tolerance (FT) • Support for MSCS clustering VMware availability product: • VMware vCenter™ Site Recovery Manager: • Decreases planned and unplanned downtime. SRM protects all of your important systems and applications with disaster recovery. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  9. VMware HA, FT, and MSCS Clustering VMware vSphere 4.1: Install, Configure, Manage – Revision A

  10. vCenter Server Availability Make VMware vCenter Server and the components it relies on highly available. vCenter Server relies on: • vCenter Server database: • Cluster the database. Refer to the specific database documentation. • Active Directory structure: • Set up with multiple redundant servers. Methods for making vCenter Server available: • Use VMware HA to protect the vCenter Server virtual machine. • Use VMware vCenter Server Heartbeat. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  11. VMware HA VMware HA: • Provides automatic restart of virtual machines in case of physical host failures • Provides high availability while reducing the need for passive standby hardware and dedicated administrators • Provides support for virtual machine failures with virtual machine monitoring and FT • Is configured, managed, and monitored through vCenter Server A cluster enabled for VMware HA and DRS can have: • Up to 32 hosts per cluster • Up to 320 virtual machines per host (regardless of the number of hosts/cluster) • Up to 3,000 virtual machines per cluster VMware vSphere 4.1: Install, Configure, Manage – Revision A

  12. VMware HA in Action LUN 4 LUN 3 LUN 2 LUN 6 LUN 5 LUN 1 virtual machine B virtual machine A virtual machine E virtual machine C virtual machine A virtual machine F virtual machine D virtual machine B host host host vCenter Server VMware vSphere 4.1: Install, Configure, Manage – Revision A

  13. Using VMware HA and DRS Together Using VMware HA and DRS results in fast rebalancing of virtual machines after VMware HA has restarted virtual machines to different hosts. Reasons why VMware HA might not be able to fail over virtual machines: • VMware HA admission control is disabled and VMware Distributed Power Management is enabled. • Required Virtual Machines to Hosts affinity rule prevents VMware HA from failing over. • Sufficient aggregated resources exist, but they are fragmented across hosts. In such cases, VMware HA uses DRS to try to adjust the cluster by: • Bringing hosts out of standby mode • Migrating virtual machines to defragment the resources VMware vSphere 4.1: Install, Configure, Manage – Revision A

  14. Detecting a Host Failure The VMware HA agent monitors the heartbeats between the primary and the secondary hosts to detect host failure. A heartbeat is sent every second (by default) over the heartbeat network. • On ESXi hosts, the management network is used. • On ESX hosts, the service console network is used. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  15. Host Isolation If a host in the cluster loses its connection to the heartbeat network but the host continues running, the host is isolated from the cluster. VMware HA waits 12 seconds before deciding that a host is isolated. virtual machine virtual machine virtual machine virtual machine virtual machine virtual machine VMware vSphere 4.1: Install, Configure, Manage – Revision A

  16. Architecture of a VMware HA Cluster vCenter Server vCenterServer agent vCenterServer agent vCenterServer agent VMware HA agent VMware HA agent VMware HA agent host host host VMware vSphere 4.1: Install, Configure, Manage – Revision A

  17. Enabling VMware HA Enable VMware HA by creating a cluster or modifying a DRS cluster. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  18. Configuring VMware HA Settings Disable Host Monitoring when performing maintenance activities on the host. Admission control helps ensure sufficient resources to provide high availability. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  19. Admission Control Policy Choices VMware vSphere 4.1: Install, Configure, Manage – Revision A

  20. Configuring Virtual Machine Options Configure options at the cluster level or per virtual machine. VM restart priority determines relative order in which virtual machines are restarted after a host failure. Host Isolation response determines what happens when a host loses the management (or service console) network but continues running. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  21. Configuring Virtual Machine Monitoring Restart a virtual machine if its VMware Tools heartbeat or VMware Tools application heartbeats are not received. Determine how quickly failures are detected. Set monitoring sensitivity for individual virtual machines. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  22. Monitoring Cluster Status The Cluster Operational Status window displays the current VMware HA operational status, including the specific status and errors for each primary and secondary host in the cluster. cluster’s Summary tab VMware vSphere 4.1: Install, Configure, Manage – Revision A

  23. Lab 23 • In this lab, you will demonstrate VMware HA functionality. • Create a cluster enabled for VMware HA. • Test VMware HA functionality. • Prepare for the next lab. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  24. Lesson Summary • Describe VMware solutions for: • High availability • Fault tolerance • Configure a VMware HA cluster VMware vSphere 4.1: Install, Configure, Manage – Revision A

  25. Lesson 2:Managing VMware HA VMware vSphere 4.1: Install, Configure, Manage – Revision A

  26. Lesson Objectives • Configure VMware HA advanced options • Configure redundant heartbeat networks • Configure redundant isolation test addresses • View the status of cluster operations • Follow best practices when configuring VMware HA clusters VMware vSphere 4.1: Install, Configure, Manage – Revision A

  27. Setting VMware HA Advanced Parameters Set advanced parameters by editing VMware HA cluster settings. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  28. Advanced Options to Control Slot Size Set default (minimum) slot size: • das.vmCpuMinMHz • das.vmMemoryMinMB • Set maximum slot size: • das.slotCpuInMHz • das.slotMemInMB VMware vSphere 4.1: Install, Configure, Manage – Revision A

  29. Planning Resources for a VMware HA/DRS Cluster How much CPU and memory resources is the cluster using now? How much reserved capacity remains? VMware vSphere 4.1: Install, Configure, Manage – Revision A

  30. Importance of Redundant Heartbeat Networks In a VMware HA cluster, heartbeats are: • Sent between the primary and the secondary hosts • Used to determine if a primary host failed • Sent over the heartbeat network The heartbeat network is: • On ESXi hosts, the management network • On ESX hosts, the service console network Redundant heartbeat networks: • Allow for the reliable detection of failures • Help prevent isolation conditions from occurring VMware vSphere 4.1: Install, Configure, Manage – Revision A

  31. Redundancy Using NIC Teaming You can use NIC teaming to create a redundant heartbeat network on ESX/ESXi hosts. NIC teaming on an ESXi host VMware vSphere 4.1: Install, Configure, Manage – Revision A

  32. Redundancy Using Additional Networks You can also create redundancy by configuring more heartbeat networks: • On ESXi hosts, add one or more VMkernel networks marked for management traffic. • On ESX hosts, add one or more service console networks. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  33. How Hosts Test for Isolation An isolation address is an IP address that is pinged to determine whether an ESX/ESXi host is isolated from the network. Hosts in the VMware HA cluster test themselves for isolation by pinging the isolation address. • By default, ESXi hosts ping the VMkernel gateway IP address. • By default, ESX hosts ping the service console default gateway IP address. As a best practice, configure redundant isolation addresses. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  34. Configuring Isolation Addresses • Ensure that your isolation addresses are reliable IP addresses. To configure more isolation addresses, set das.isolationaddress#. When more isolation addresses are configured, increase the value of das.failuredetectiontime. To prevent use of the default isolation address, set das.usedefaultisolationaddress. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  35. Network Configuration and Maintenance • Before changing the networking configuration on the ESX/ESXi hosts (adding port groups, removing vSwitches): • Deselect EnableHost Monitoring. • Place the host inmaintenance mode. • These steps prevent unwanted attempts to fail over virtual machines. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  36. Lab 24 • In this lab, you will modify slot sizes and admission control. • Use the Resource Allocation tab to determine resource use. • Manage VMware HA slot size. • Configure a VMware HA cluster with strict admission control. • Configure a VMware HA cluster with flexible admission control. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  37. Lab 25 (Optional) • Do not perform this lab unless agreed to by your instructor. • In this lab, you will configure VMware HA network redundancy. • Enable technical support mode on an ESXi host. • Test default VMware HA failure detection time. • Modify and test VMware HA failure detection time. • Configure management network redundancy. • Configure VMware HA host isolation response. • Test network isolation functionality. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  38. Lesson Summary • Configure VMware HA advanced options • Configure redundant heartbeat networks • Configure redundant isolation test addresses • View the status of cluster operations • Follow best practices when configuring VMware HA clusters VMware vSphere 4.1: Install, Configure, Manage – Revision A

  39. Lesson 3:FT VMware vSphere 4.1: Install, Configure, Manage – Revision A

  40. Lesson Objectives • Compare VMware HA, FT, and MSCS clustering • List FT requirements and limitations • Describe FT operation • Configure, monitor, and test a fault-tolerant virtual machine VMware vSphere 4.1: Install, Configure, Manage – Revision A

  41. What Is FT? FT: • Provides a higher level of business continuity than VMware HA • Provides zero downtime and zero data loss for applications FT can be used for: • Any application that needs to be available at all times • Custom applications that have no other way of doing clustering • Cases where high availability might be provided through Microsoft Cluster Service but MSCS is too complicated to configure and maintain FT can be used with DRS: • Fault-tolerant virtual machines benefit from better initial placement and are included in the cluster’s load-balancing calculations. VMware vSphere 4.1: Install, Configure, Manage – Revision A

  42. FT provides zero-downtime, zero-data-loss protection to virtual machines in a VMware HA cluster. FT in Action vLockstep technology vLockstep technology newprimaryVM secondaryVM primary VM new secondary VM VMware vSphere 4.1: Install, Configure, Manage – Revision A

  43. Requirements for FT VMware vSphere 4.1: Install, Configure, Manage – Revision A

  44. How FT Works primary virtual machine secondary virtual machine VMkernel VMkernel VMM VMM Log update? Log read? record logs log buffer log buffer Heartbeat? read/write read single copy of disks on shared storage VMware vSphere 4.1: Install, Configure, Manage – Revision A

  45. FT Guidelines Check the requirements and limitations of FT. Ensure enough ESX/ESXi hosts for fault-tolerant virtual machines: • No more than four fault-tolerant virtual machines (primaries or secondaries) on any single host Store ISOs on shared storage for continuous access: • Especially if used for important operations Disable BIOS-based power management: • Prevents the secondary virtual machine from having insufficient CPU resources VMware vSphere 4.1: Install, Configure, Manage – Revision A

  46. Enabling FT Logging on a Host For each ESX/ESXi host in the cluster, create a VMkernel networking interface to use for FT logging. enabling FT logging on a vNetwork standard switch VMware vSphere 4.1: Install, Configure, Manage – Revision A

  47. Enabling FT on a Virtual Machine • After you turn on FT, the Summary tab on the primary virtual machine reports FT information. virtual machine’s Summary tab VMware vSphere 4.1: Install, Configure, Manage – Revision A

  48. Use the commands from the shortcut menu to test and manage the virtual machine enabled for FT. Managing Virtual Machines Enabled for FT VMware vSphere 4.1: Install, Configure, Manage – Revision A

  49. Lab 26 and eLearning Activity Do lab 26 if you are using a lab environment that supports FT. In this lab, you will configure FT for a virtual machine and verify that FT works. • Enable FT logging. • Activate FT. • Test FT. • Disable FT. Otherwise, perform the eLearning activity: http://mylearn.vmware.com/register.cfm?course=73276 VMware vSphere 4.1: Install, Configure, Manage – Revision A

  50. Lesson Summary • Compare VMware HA, FT, and MSCS clustering • List FT requirements and limitations • Describe FT operation • Configure, monitor, and test a fault-tolerant virtual machine VMware vSphere 4.1: Install, Configure, Manage – Revision A

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