6.7
Table Of Contents
- vSphere Availability
- Contents
- About vSphere Availability
- Business Continuity and Minimizing Downtime
- Creating and Using vSphere HA Clusters
- Providing Fault Tolerance for Virtual Machines
- How Fault Tolerance Works
- Fault Tolerance Use Cases
- Fault Tolerance Requirements, Limits, and Licensing
- Fault Tolerance Interoperability
- Preparing Your Cluster and Hosts for Fault Tolerance
- Using Fault Tolerance
- Best Practices for Fault Tolerance
- Legacy Fault Tolerance
- Troubleshooting Fault Tolerant Virtual Machines
- Hardware Virtualization Not Enabled
- Compatible Hosts Not Available for Secondary VM
- Secondary VM on Overcommitted Host Degrades Performance of Primary VM
- Increased Network Latency Observed in FT Virtual Machines
- Some Hosts Are Overloaded with FT Virtual Machines
- Losing Access to FT Metadata Datastore
- Turning On vSphere FT for Powered-On VM Fails
- FT Virtual Machines not Placed or Evacuated by vSphere DRS
- Fault Tolerant Virtual Machine Failovers
- vCenter High Availability
- Plan the vCenter HA Deployment
- Configure the Network
- Configure vCenter HA With the Basic Option
- Configure vCenter HA With the Advanced Option
- Manage the vCenter HA Configuration
- Set Up SNMP Traps
- Set Up Your Environment to Use Custom Certificates
- Manage vCenter HA SSH Keys
- Initiate a vCenter HA Failover
- Edit the vCenter HA Cluster Configuration
- Perform Backup and Restore Operations
- Remove a vCenter HA Configuration
- Reboot All vCenter HA Nodes
- Change the Appliance Environment
- Collecting Support Bundles for a vCenter HA Node
- Troubleshoot Your vCenter HA Environment
- Patching a vCenter High Availability Environment
- Using Microsoft Clustering Service for vCenter Server on Windows High Availability
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For legacy ESXi 4.x hosts, vSphere HA writes
to /var/log/vmware/fdm on local disk, as well as syslog if it is
configured.
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For legacy ESX 4.x hosts, vSphere HA writes
to /var/log/vmware/fdm.
Secure vSphere HA
logins
vSphere HA logs onto the vSphere HA agents using a user account,
vpxuser, created by vCenter Server. This account is the same account
used by vCenter Server to manage the host. vCenter Server creates a
random password for this account and changes the password periodically.
The time period is set by the vCenter Server
VirtualCenter.VimPasswordExpirationInDays setting. Users with
administrative privileges on the root folder of the host can log in to the
agent.
Secure communication All communication between vCenter Server and the vSphere HA agent is
done over SSL. Agent-to-agent communication also uses SSL except for
election messages, which occur over UDP. Election messages are verified
over SSL so that a rogue agent can prevent only the host on which the
agent is running from being elected as a master host. In this case, a
configuration issue for the cluster is issued so the user is aware of the
problem.
Host SSL certificate
verification required
vSphere HA requires that each host have a verified SSL certificate. Each
host generates a self-signed certificate when it is booted for the first time.
This certificate can then be regenerated or replaced with one issued by an
authority. If the certificate is replaced, vSphere HA needs to be reconfigured
on the host. If a host becomes disconnected from vCenter Server after its
certificate is updated and the ESXi or ESX Host agent is restarted, then
vSphere HA is automatically reconfigured when the host is reconnected to
vCenter Server. If the disconnection does not occur because vCenter
Server host SSL certificate verification is disabled at the time, verify the
new certificate and reconfigure vSphere HA on the host.
vSphere HA Admission Control
vSphere HA uses admission control to ensure that sufficient resources are reserved for virtual machine
recovery when a host fails.
Admission control imposes constraints on resource usage. Any action that might violate these constraints
is not permitted. Actions that might be disallowed include the following examples:
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Powering on a virtual machine
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Migrating a virtual machine
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Increasing the CPU or memory reservation of a virtual machine
vSphere Availability
VMware, Inc. 20