Virtualisation is now possible on the ODA whatever it is an ODA Lite or HA. The virtualisation is based on KVM and integrated with odacli for Bare Metal installation. Virtualisation has got the advantage to allocate resources to databases and applications on the same physical server. But what is the High Availability solution I have for virtualization on the ODA?

Virtualisation solutions

There is 2 kind of virtualisation.

Virtual Machines

Virtual Machines is also called Compute Instances.

  • These VM are mainly used for application
  • They support various OS like linux, windows, solaris, …

In order to be able to create a Compute Instance, we need :

  • A CPU Pool
  • A VM Storage
  • Virtual Network
  • Virtual Disks

VM Storage:

  • Central location storing resources essential for creating and managing VM as ISO files, VM configuration files, Virtual Disks
  • Created on the ACFS it can be easily relocate in case the physical server, where the VM is running, fails

Virtual Network:

A Virtual Disks is:

  • Created in VM storage
  • Provides additional storage to the VM
  • Can be attached and detach later on
  • Expanding VM file system storage or creating a new file system

A Compute Instance can be started, stopped, cloned and restarted independently.

Auto start can be enabled or disabled whatever ODA we are using (Single-node or HA ODA models), see below :

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i 'Auto Start'
               Auto start:  YES
               
[root@dbioda02 ~]# odacli modify-vm -h | grep -i 'autostart'
    --autostart,-as            Enables autostart for the VM
    --no-autostart,-no-as      Disables autostart for the VM
    
[root@dbioda02 ~]# odacli modify-vm -n vmdoag -no-as

Job details
----------------------------------------------------------------
                     ID:  8cce5d5a-3f84-4140-a3eb-13646db774bc
            Description:  VM vmdoag modification
                 Status:  Created
                Created:  December 20, 2022 4:07:37 PM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------

[root@dbioda02 ~]# odacli describe-job -i 8cce5d5a-3f84-4140-a3eb-13646db774bc

Job details
----------------------------------------------------------------
                     ID:  8cce5d5a-3f84-4140-a3eb-13646db774bc
            Description:  VM vmdoag modification
                 Status:  Success
                Created:  December 20, 2022 4:07:37 PM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------
Validate dependency resources            December 20, 2022 4:07:37 PM CET    December 20, 2022 4:07:38 PM CET    Success
Define VM locally                        December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:38 PM CET    Success
Edit VM CRS Configuration                December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:38 PM CET    Success
Save domain in ACFS                      December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:38 PM CET    Success
Define VM globally                       December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:38 PM CET    Success
Modify VM metadata                       December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:38 PM CET    Success
Persist metadata                         December 20, 2022 4:07:38 PM CET    December 20, 2022 4:07:39 PM CET    Success

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i 'Auto Start'
               Auto start:  NO

DB Systems

  • These VM are dedicated to host database
  • Hard partitioning is possible
  • It is like an odacli integrated in the Bare Metal itself
  • It will permit network segregation and OS segregation
  • They are mainly used for licensing reason in Enterprise Edition. CPU core of the ODA will not be reduced. Shared DB System CPU pool will be created according to the number of cores being licensed, and DB System will be run on those CPU Pool.

For DB Systems there is a few requirement that needs to be understood:

  • 200 GB per DB System will be needed on the DATA Group to create the virtual host
  • We can only host 1 database per DB System
  • Database created in the DB System can only run ASM and not ACFS
  • In version 19.X it possible to create CDB or non CDB database
  • With current ODA 19.17 version it is possible to create database in DB System in versions 21.8, 21.7, 21.6, 21.5, 21.4, 19.17, 19.16, 19.15, 19.14, and 19.13.

On the other hand the DB System will required a more complex installation, will use more resources (Memory and CPU) and add more maintenance work (during ODA patching we will need to additionally patch all DB Systems).

High Availability with Compute Instance

HA (High Availability) is only possible with ODA HA models (2 nodes with ACFS Storage).
By default VM are created with autostart and failover enabled for HA models:

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i 'Auto Start\|Fail over'
               Auto start:  YES
                Fail over:  YES

It is of course possible to enable or disable failover option.

What is happening in case the physical node, where the VM is running, is crashing ?
There will be one attempt to restart the VM once before failing over to the different node on HA models.

Relocate VM

We can easily relocate the VM on the other node. Currently my VM is running on node 0, named, dbioda02.

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i node
             Current node:  dbioda02
           Preferred node:  dbioda02

As we can see, we can set a preferred node. This preferred node can be easily change.

[root@dbioda02 ~]# odacli modify-vm -h | grep -i pref-node
    --pref-node,-pn            Defines the preferred node to run the VM, use

To be able to relocate the VM on the other node the graphical settings should be put on 127.0.0.1 if not already done, otherwise the command will failed with following error : 

internal error: qemu unexpectedly closed the monitor: 2022-09-12T21:05:45.531641Z qemu-system-x86_64: -vnc 10.36.0.232:0: Failed to bind socket: Cannot assign requested address
[root@dbioda02 ~]# odacli modify-vm -n vmdoag -g "vnc,listen=127.0.0.1"

Job details
----------------------------------------------------------------
                     ID:  74028fc9-d680-4565-ba94-cce0d0bb5677
            Description:  VM vmdoag modification
                 Status:  Created
                Created:  December 21, 2022 8:35:50 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------

To relocate the VM on the other node, either we can stop the VM and start it on the other node :

odacli start-vm -n vmdoag -nn dbioda03

Or use the migrate command :

odacli migrate-vm -n vmdoag -to dbioda03

Currently my VMs is running on my node 0, dbioda02, my node 1 being dbioda03. Pay attention on which nodes, the KVM processes are running.

[root@dbioda02 ~]# ps -ef | grep -i [k]vm
qemu     36043     1  0 Dec20 ?        00:08:42 /usr/bin/qemu-system-x86_64 -name guest=vmdoag,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-vmdoag/master-key.aes -enable-fips -machine pc-i440fx-4.2,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX-IBRS -m 6144 -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid d71ecbc9-30f6-43c6-b6ea-7649fffa60b6 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=36,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x4.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x4 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x4.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x4.0x2 -blockdev {"driver":"file","filename":"/u05/app/sharedrepo/vmsdoag/.ACFS/snaps/vm_vmdoag/vmdoag","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"driver":"qcow2","file":"libvirt-2-storage","backing":null} -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=libvirt-2-format,id=virtio-disk0,bootindex=1 -device ide-cd,bus=ide.0,unit=0,id=ide0-0-0 -netdev tap,fd=38,id=hostnet0,vhost=on,vhostfd=39 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:3c:2a:60,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 10.36.0.232:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
root     36047     2  0 Dec20 ?        00:00:00 [kvm-nx-lpage-re]
root     36053     2  0 Dec20 ?        00:00:00 [kvm-pit/36043]

[root@dbioda03 ~]# ps -ef | grep -i [k]vm
[root@dbioda03 ~]#

Let’s relocate the VM on dbioda03 node.

[root@dbioda02 ~]# odacli migrate-vm -n vmdoag -to dbioda03

Job details
----------------------------------------------------------------
                     ID:  ab5c7fd2-f21b-4f0d-af70-34747e333e75
            Description:  VM vmdoag migration
                 Status:  Created
                Created:  December 21, 2022 8:49:08 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------

[root@dbioda02 ~]# odacli describe-job -i ab5c7fd2-f21b-4f0d-af70-34747e333e75

Job details
----------------------------------------------------------------
                     ID:  ab5c7fd2-f21b-4f0d-af70-34747e333e75
            Description:  VM vmdoag migration
                 Status:  Success
                Created:  December 21, 2022 8:49:08 AM CET
                Message:

Task Name                                Start Time                          End Time                            Status
---------------------------------------- ----------------------------------- ----------------------------------- ----------
Validate migrate prerequisites           December 21, 2022 8:49:08 AM CET    December 21, 2022 8:49:08 AM CET    Success
Migrate VM                               December 21, 2022 8:49:08 AM CET    December 21, 2022 8:49:26 AM CET    Success

Let’s check the details for the VM to confirm the current node information.

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i node
             Display Port:  Check node dbioda03
             Current node:  dbioda03
           Preferred node:  dbioda02

The current node is now dbioda03.

Let’s check that the KVM processes are really running on dbiod03 node.

[root@dbioda02 ~]# ps -ef | grep -i [k]vm
[root@dbioda02 ~]#

[root@dbioda03 ~]# ps -ef | grep -i [k]vm
qemu     76320     1  4 08:49 ?        00:00:54 /usr/bin/qemu-system-x86_64 -name guest=vmdoag,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-vmdoag/master-key.aes -enable-fips -machine pc-i440fx-4.2,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX-IBRS -m 6144 -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid d71ecbc9-30f6-43c6-b6ea-7649fffa60b6 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=36,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x4.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x4 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x4.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x4.0x2 -blockdev {"driver":"file","filename":"/u05/app/sharedrepo/vmsdoag/.ACFS/snaps/vm_vmdoag/vmdoag","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"driver":"qcow2","file":"libvirt-2-storage","backing":null} -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=libvirt-2-format,id=virtio-disk0,bootindex=1 -device ide-cd,bus=ide.0,unit=0,id=ide0-0-0 -netdev tap,fd=38,id=hostnet0,vhost=on,vhostfd=39 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:3c:2a:60,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
root     76336     2  0 08:49 ?        00:00:00 [kvm-nx-lpage-re]
root     76342     2  0 08:49 ?        00:00:00 [kvm-pit/76320]

Let’s crash dbiod03 node and see if a failover of the VM is automatically done on the dbioda02 node.

[root@dbioda03 ~]# systemctl poweroff
Connection to 10.36.0.233 closed by remote host.
Connection to 10.36.0.233 closed.

We can see that the KVM processes have been automatically started on dbioda02 node.

[root@dbioda02 ~]# ps -ef | grep -i [k]vm
qemu     19412     1 18 09:12 ?        00:00:46 /usr/bin/qemu-system-x86_64 -name guest=vmdoag,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-3-vmdoag/master-key.aes -enable-fips -machine pc-i440fx-4.2,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX-IBRS -m 6144 -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid d71ecbc9-30f6-43c6-b6ea-7649fffa60b6 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=36,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x4.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x4 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x4.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x4.0x2 -blockdev {"driver":"file","filename":"/u05/app/sharedrepo/vmsdoag/.ACFS/snaps/vm_vmdoag/vmdoag","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":false,"driver":"qcow2","file":"libvirt-2-storage","backing":null} -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=libvirt-2-format,id=virtio-disk0,bootindex=1 -device ide-cd,bus=ide.0,unit=0,id=ide0-0-0 -netdev tap,fd=38,id=hostnet0,vhost=on,vhostfd=39 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:3c:2a:60,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on
root     19427     2  0 09:12 ?        00:00:00 [kvm-nx-lpage-re]
root     19433     2  0 09:12 ?        00:00:00 [kvm-pit/19412]

Following automatic failover, and due to the fact dbioda03 node is still power off, the VM description is showing current node as N/A.

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i node
             Current node:  N/A
           Preferred node:  dbioda02

Once dbioda03 node is up and running again, the output is showing correctly dbioda02 node as current node.

[root@dbioda02 ~]# odacli describe-vm -n vmdoag | grep -i node
             Current node:  dbioda02
           Preferred node:  dbioda02

High Availability with DB Systems

With DB Systems we can either create a single-instance database or a RAC database with 2 instances. We will the benefit here from the RAC advantages for DB Systems High Availability.

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Marc Wagner