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HP BL680c XenServer Administrator's Guide 4.1.0 - Page 14

Master failures, 7.3. Pool failures, 7.4. Coping with Failure due to Configuration Errors

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XenServer Hosts and resource pools When a member XenServer Host fails, there may be VMs still registered in the running state. If you are sure that the member XenServer Host is definitely down, and that the VMs have not been brought up on another XenServer Host in the pool, use the xe vm-reset-powerstate CLI command to forcibly halt the VMs. See Section 5.4.22.21, "vm-reset-powerstate" for more details. 2.7.2. Master failures Every member of a resource pool contains all the information necessary to take over the role of master if required. When a master node fails, the following sequence of events occurs: 1. The members realize that communication has been lost and each retry for sixty seconds 2. Each member then puts itself into emergency mode, whereby the member XenServer Hosts will now accept only the pool-emergency commands (xe pool-emergency-reset-master and xe pool-emergency-transition-to-master). If the master comes back up at this point, it will reestablish communication with its members, they will leave emergency mode, and operation will return to normal. If the master is really dead, though, you should choose one of the members and issue to it the command xe pool-emergency-transition-to-master. Once it has become the master, issue the command xe poolrecover-slaves and the members will now point to the new master. If you repair or replace the server that was the original master, you can simply bring it up, install the XenServer Host software, and add it to the pool. Since the XenServer Hosts in the pool are enforced to be homogeneous, there is no real need to make the replaced server the master. When a member XenServer Host is transitioned to being a master, you should also check that the default pool storage repository is set to an appropriate value. This can be done using the xe pool-param-list command and verifying that the default-SR parameter is pointing to a valid storage repository. 2.7.3. Pool failures In the unfortunate event that your entire resource pool fails, you will need to re-create the pool database from scratch. Be sure to regularly back up your pool-metadata using the xe pool-dump-database CLI command (see Section 5.4.11.2, "pool-dump-database"). Procedure 2.9. To restore a completely failed pool 1. Install a fresh set of hosts, and apply your Enterprise Edition license to them. Do not pool them up at this stage. 2. For the host nominated as the master, restore the pool database from your backup via the xe poolrestore-database (see Section 5.4.11.8, "pool-restore-database") CLI command. 3. Connect to the master host via XenCenter and ensure that all your shared storage and VMs are available again. 4. Perform a pool join operation on the remaining freshly installed member hosts, and start up your VMs on the appropriate hosts. 2.7.4. Coping with Failure due to Configuration Errors If the physical host machine is operational but the software or host configuration is corrupted: 8

Section	Page
XenServer Administrator's Guide	1
Table of Contents	4
Chapter 1. Overview	7
1.1. XenServer Hosts and resource pools	7
1.2. Networking	7
1.3. Storage	7
1.4. Command Line Interface	8
1.5. How this Guide relates to other documentation	8
Chapter 2. XenServer Hosts and resource pools	9
2.1. Requirements for creating resource pools	9
2.2. Creating a resource pool	10
2.3. Adding shared storage	10
2.4. Installing and managing VMs on shared storage	11
2.5. Removing a XenServer Host from a resource pool	11
2.6. Backups	12
2.7. Coping with machine failures	13
2.7.1. Member failures	13
2.7.2. Master failures	14
2.7.3. Pool failures	14
2.7.4. Coping with Failure due to Configuration Errors	14
2.7.5. Physical Machine failure	15
Chapter 3. Storage	17
3.1. Overview	17
3.1.1. Storage repositories (SRs)	17
3.1.2. Virtual Disk Images (VDI)	17
3.1.3. Managing Storage	18
3.2. Storage Repository Types	18
3.2.1. Local Disks	19
3.2.2. Local hotplug devices	19
3.2.3. Shared Network Attached Storage using NFS	19
3.2.4. Shared iSCSI Storage	20
3.2.4.1. XenServer Host iSCSI configuration	21
3.2.5. Shared LVM storage over FC or iSCSI hardware HBAs	21
3.2.6. Shared NetApp Storage	22
3.3. Storage configuration examples	24
3.3.1. Creating Storage Repositories	24
3.3.2. Probing an SR	25
3.3.3. Creating a local LVM SR (lvm)	27
3.3.4. Creating a local EXT3 SR (ext)	27
3.3.5. Creating a shared NFS SR (nfs)	27
3.3.6. Creating a shared LVM over iSCSI SR using the software iSCSI initiator (lvmoiscsi)	28
3.3.7. Creating a shared LVM over Fibre Channel or iSCSI HBA SR (lvmohba)	28
3.3.8. Creating a shared NetApp SR over iSCSI	31
3.4. Managing Storage Repositories	31
3.4.1. Destroying or forgetting a SR	31
3.4.2. Introducing a SR	32
3.4.3. Converting local Fibre Channel SRs to shared SRs	32
3.4.4. Moving Virtual Disk Images (VDIs) between SRs	33
3.4.4.1. Copying all of a VM's VDIs to a different SR	33
3.4.4.2. Copying individual VDIs to a different SR	33
3.4.5. Managing VDIs in a Netapp SR	34
3.4.6. Taking VDI snapshots with a Netapp SR	34
3.4.7. Adjusting the disk IO scheduler for an LVM-based SR	34
3.5. Managing Host Bus Adapters (HBAs)	34
3.5.1. Sample QLogic iSCSI HBA setup	35
3.5.2. Removing HBA-based FC or iSCSI device entries	35
3.6. Virtual disk QoS settings (Enterprise Edition only)	35
Chapter 4. Networking	37
4.1. Networking configuration performed during Host installation	37
4.2. Managing networking configuration for standalone XenServer Hosts	38
4.2.1. Creating networks	38
4.2.2. Connecting Virtual Machines (VMs) to networks	39
4.2.3. Creating VLANs	39
4.2.4. Creating NIC bonds	40
4.2.4.1. Creating a NIC bond on a dual-NIC host	40
4.2.4.2. Controlling the MAC address of the bond	41
4.2.4.3. Reverting NIC bonds	42
4.2.5. Controlling Quality of Service (QoS)	42
4.2.6. Dedicating a NIC to storage traffic	42
4.2.7. Changing networking configuration options	43
4.2.7.1. Hostname	43
4.2.7.2. DNS servers	43
4.2.7.3. XenServer Host IP address configuration	43
4.2.7.4. Management interface	43
4.2.7.5. Disabling management access	44
4.3. Managing networking configuration for XenServer pools	44
4.3.1. Networks in resource pools	44
4.3.2. Creating NIC bonds in resource pools	44
4.3.2.1. Adding NIC bonds to new resource pools	45
4.3.2.2. Adding NIC bonds to an existing pool	47
4.3.3. Changing XenServer Host IP address configuration in resource pools	48
4.3.4. NIC/PIF ordering	49
4.3.4.1. Verifying NIC ordering	49
4.3.4.2. Re-ordering NICs	50
4.4. Networking Troubleshooting	51
4.4.1. Diagnosing network corruption	51
4.4.2. Recovering from a bad network configuration	52
Chapter 5. Command line interface	53
5.1. Basic xe syntax	53
5.2. Special characters and syntax	54
5.3. Command types	55
5.3.1. Parameter types	56
5.3.2. Low-level param commands	56
5.3.3. Low-level list commands	57
5.4. xe command reference	58
5.4.1. Bonding commands	58
5.4.1.1. bond-create	58
5.4.1.2. bond-destroy	58
5.4.2. CD commands	59
5.4.2.1. cd-list	60
5.4.3. Console commands	60
5.4.4. Event commands	60
5.4.4.1. event-wait	61
5.4.5. Host (XenServer Host) commands	61
5.4.5.1. host-backup	64
5.4.5.2. host-bugreport-upload	64
5.4.5.3. host-crashdump-destroy	64
5.4.5.4. host-crashdump-upload	64
5.4.5.5. host-disable	65
5.4.5.6. host-dmesg	65
5.4.5.7. host-emergency-management-reconfigure	65
5.4.5.8. host-enable	65
5.4.5.9. host-evacuate	65
5.4.5.10. host-forget	65
5.4.5.11. host-get-system-status	66
5.4.5.12. host-get-system-status-capabilities	66
5.4.5.13. host-is-in-emergency-mode	67
5.4.5.14. host-license-add	67
5.4.5.15. host-license-view	67
5.4.5.16. host-logs-download	67
5.4.5.17. host-management-disable	68
5.4.5.18. host-management-reconfigure	68
5.4.5.19. host-reboot	68
5.4.5.20. host-restore	69
5.4.5.21. host-set-hostname-live	69
5.4.5.22. host-shutdown	69
5.4.5.23. host-syslog-reconfigure	69
5.4.6. Log commands	69
5.4.6.1. log-get-keys	70
5.4.6.2. log-reopen	70
5.4.6.3. log-set-output	70
5.4.7. Network commands	70
5.4.7.1. network-create	71
5.4.7.2. network-destroy	71
5.4.8. Patch (update) commands	71
5.4.8.1. patch-apply	71
5.4.8.2. patch-clean	71
5.4.8.3. patch-pool-apply	72
5.4.8.4. patch-precheck	72
5.4.8.5. patch-upload	72
5.4.9. PBD commands	72
5.4.9.1. pbd-create	72
5.4.9.2. pbd-destroy	73
5.4.9.3. pbd-plug	73
5.4.9.4. pbd-unplug	73
5.4.10. PIF commands	73
5.4.10.1. pif-forget	75
5.4.10.2. pif-introduce	75
5.4.10.3. pif-plug	75
5.4.10.4. pif-reconfigure-ip	75
5.4.10.5. pif-scan	75
5.4.10.6. pif-unplug	75
5.4.11. Pool commands	75
5.4.11.1. pool-designate-new-master	76
5.4.11.2. pool-dump-database	76
5.4.11.3. pool-eject	76
5.4.11.4. pool-emergency-reset-master	77
5.4.11.5. pool-emergency-transition-to-master	77
5.4.11.6. pool-join	77
5.4.11.7. pool-recover-slaves	77
5.4.11.8. pool-restore-database	77
5.4.11.9. pool-sync-database	77
5.4.12. Storage Manager commands	77
5.4.13. SR commands	78
5.4.13.1. sr-create	79
5.4.13.2. sr-destroy	79
5.4.13.3. sr-forget	79
5.4.13.4. sr-introduce	80
5.4.13.5. sr-probe	80
5.4.13.6. sr-scan	80
5.4.14. Task commands	80
5.4.14.1. task-cancel	81
5.4.15. Template commands	81
5.4.15.1. template-export	86
5.4.16. Update commands	86
5.4.16.1. update-upload	86
5.4.17. User commands	86
5.4.17.1. user-password-change	86
5.4.18. VBD commands	86
5.4.18.1. vbd-create	88
5.4.18.2. vbd-destroy	88
5.4.18.3. vbd-eject	88
5.4.18.4. vbd-insert	88
5.4.18.5. vbd-plug	88
5.4.18.6. vbd-unplug	88
5.4.19. VDI commands	89
5.4.19.1. vdi-clone	90
5.4.19.2. vdi-copy	90
5.4.19.3. vdi-create	90
5.4.19.4. vdi-destroy	90
5.4.19.5. vdi-forget	91
5.4.19.6. vdi-import	91
5.4.19.7. vdi-introduce	91
5.4.19.8. vdi-resize	91
5.4.19.9. vdi-snapshot	91
5.4.19.10. vdi-unlock	91
5.4.20. VIF commands	91
5.4.20.1. vif-create	93
5.4.20.2. vif-destroy	93
5.4.20.3. vif-plug	93
5.4.20.4. vif-unplug	93
5.4.21. VLAN commands	93
5.4.21.1. vlan-create	93
5.4.21.2. vlan-destroy	93
5.4.22. VM commands	93
5.4.22.1. vm-cd-add	98
5.4.22.2. vm-cd-eject	98
5.4.22.3. vm-cd-insert	98
5.4.22.4. vm-cd-list	98
5.4.22.5. vm-cd-remove	99
5.4.22.6. vm-clone	99
5.4.22.7. vm-compute-maximum-memory	99
5.4.22.8. vm-copy	99
5.4.22.9. vm-crashdump-list	100
5.4.22.10. vm-create	100
5.4.22.11. vm-destroy	100
5.4.22.12. vm-disk-add	100
5.4.22.13. vm-disk-list	101
5.4.22.14. vm-disk-remove	101
5.4.22.15. vm-export	101
5.4.22.16. vm-import	101
5.4.22.17. vm-install	102
5.4.22.18. vm-memory-shadow-multiplier-set	102
5.4.22.19. vm-migrate	102
5.4.22.20. vm-reboot	103
5.4.22.21. vm-reset-powerstate	103
5.4.22.22. vm-resume	103
5.4.22.23. vm-shutdown	103
5.4.22.24. vm-start	103
5.4.22.25. vm-suspend	104
5.4.22.26. vm-uninstall	104
5.4.22.27. vm-vcpu-hotplug	104
5.4.22.28. vm-vif-list	104
Chapter 6. Troubleshooting	105
6.1. XenServer Host logs	105
6.1.1. Sending log messages to a central server	105
6.2. Troubleshooting connections between XenCenter and the XenServer Host	106
6.3. Special debug boot options	106

Match case Limit results 1 per page

XenServer Hosts

and resource pools

When a member XenServer Host fails, there may be VMs still registered in the

running

state. If you are sure

that the member XenServer Host is definitely down, and that the VMs have not been brought up on another

XenServer Host in the pool, use the

xe vm-reset-powerstate

CLI command to forcibly halt the VMs. See

Section 5.4.22.21, “vm-reset-powerstate” for more details.

2.7.2. Master failures

Every member of a resource pool contains all the information necessary to take over the role of master if

required. When a master node fails, the following sequence of events occurs:

The members realize that communication has been lost and each retry for sixty seconds

2. Each member then puts itself into emergency mode, whereby the member XenServer Hosts will now

accept only the pool-emergency commands (

xe pool-emergency-reset-master

and

xe pool-emergen-

cy-transition-to-master

If the master comes back up at this point, it will reestablish communication with its members, they will leave

emergency mode, and operation will return to normal.

If the master is really dead, though, you should choose one of the members and issue to it the command

xe pool-emergency-transition-to-master

. Once it has become the master, issue the command

xe pool-

recover-slaves

and the members will now point to the new master.

If you repair or replace the server that was the original master, you can simply bring it up, install the XenServ-

er Host software, and add it to the pool. Since the XenServer Hosts in the pool are enforced to be homoge-

neous, there is no real need to make the replaced server the master.

When a member XenServer Host is transitioned to being a master, you should also check that the default

pool storage repository is set to an appropriate value. This can be done using the

xe pool-param-list

command and verifying that the

default-SR

parameter is pointing to a valid storage repository.

2.7.3. Pool failures

In the unfortunate event that your entire resource pool fails, you will need to re-create the pool database from

scratch. Be sure to regularly back up your pool-metadata using the

xe pool-dump-database

CLI command

(see Section 5.4.11.2, “pool-dump-database”).

Procedure 2.9. To restore a completely failed pool

Install a fresh set of hosts, and apply your Enterprise Edition license to them. Do not pool them up

at this stage.

For the host nominated as the master, restore the pool database from your backup via the

xe pool-

restore-database

(see Section 5.4.11.8, “pool-restore-database”) CLI command.

Connect to the master host via XenCenter and ensure that all your shared storage and VMs are avail-

able again.

Perform a pool join operation on the remaining freshly installed member hosts, and start up your VMs

on the appropriate hosts.

2.7.4. Coping with Failure due to Configuration Errors

If the physical host machine is operational but the software or host configuration is corrupted: