OLVM Gluster data domain healing - (Addressing split brain)

 

In recent years, the tremendous growth of applications, and these applications started generating huge volumes of data be it from mobile devices or be it from the web. As more and more such applications are being built, they needed to deliver the content directly to the user at a faster rate irrespective of if they are using a Mobile, Tablet, Laptop, Desktop, or any such device.  Along with this, handling a larger volume of files became a challenge, needs a lot of Metadata related to the file needs to be stored and accessed when needed. Data storage once looked very easy, became a big challenge now.

Storage technologies are rapidly changing in the last 3 decades, Current trend is towards software-driven data center technologies. Now we have software-driven cluster files systems such as Gluster, which gives you more elasticity and scalability. 

In the clustered environment there is a possibility you will face this split-brain scenario. In simple terms, split-brain occurs when two nodes of a cluster are disconnected. Each node thinks the other one is not working.

Azure template creation for DB - Part 2 ( Cloning new VM using snap disks)

Intro

In this era, cloud technology is booming at a rapid pace and businesses are focusing on optimizing IT infrastructure workloads by adopting cloud models like AWS, Azure, GCP, and OCI. Cloud technologies enable the organization to get on-demand services and get the advantage of quick environment provisioning. A few years back organizations were hesitant to move to the cloud due to security concerns. But everything has changed because as all cloud providers have come up with strong protection for data using various encryption technologies.

Whenever you need to build a new database environment for customers, Azure cloud makes this super easy using the snapshot feature. This enables the fast provision of new environments for complex database systems like Oracle. Even this feature can be used as a backup feature for major database changes.

The current oracle image does not consist of Oracle ASM.  In this blog, I will give an insight into how to clone VM using snap disks.

1. VM cloning steps

My Azure template creation for DB - Part 1 blog: https://chanaka-dbhelp.blogspot.com/2022/06/azure-template-creation-for-db.html illustrates the steps to create a snapshot disk with software-only installations.

In this article, I will elaborate on how to clone the new VM using snapshot disks.

OLVM intergration with OEM 13c - (OLVM Monitoring)

 

Intro

Nowadays businesses heavily depend on online mission-critical databases and applications. The online market is 24X7 so it's important they must be on top of the infrastructure monitoring. This helps system engineers, and database engineers to proactively react to alerts before they become major incidents. Monitoring and alerting play a vital role in enterprise IT  infrastructure. 

Companies are absorbing the oracle virtualization platform to host their databases and applications. It's of paramount importance to get alerts from the virtualization environment. Recently oracle integrate OLVM with oracle 13c OEM, which eases the administration overhead and helps the database administrators to manage infrastructure using the centralized console. Oracle 13c OEM is a well-mature product for monitoring and alerting, Also has many features and flexibility to tune the alerting as per the infrastructure.

In this article, I will cover the steps of how can we integrate OLVM with OEM13c.

Configure Storage domain (OLVM) - Part 4/6

 

Intro

I hope the last few articles were helpful to start a new journey with OLVM (Oracle Linux Virtual Manager). As we configured the KVM on the OLVM environment the next step is to configure the storage domain. VMs disks and snapshots are stored under storage domains.  

OLVM - Oracle VM hard partitioning – Addressing oracle licensing policy

Intro 

Virtualized platform with x86 architecture is making an enormous impact on saving IT infrastructure expenditure. Successful implementation is determined by whether the virtualized system reflects an organization's needs and goals. Some organizations lose their grip on compliance due to a lack of understanding of licensing policies. In my view, licensing plays a crucial role when selecting the correct virtual platform. Before coming to any conclusion I would recommend you assess the organization's IT infrastructure servers and categorize them into databases and applications. This helps you plan which servers are migrating to VM platforms and decide the architecture choices to consolidate the servers.

This categorization helps you to decide which virtualized platforms are suitable for the organization in terms of licensing and consolidation. If there are many oracle databases residing on oracle I would recommend you move to Oracle Virtualization. Oracle VM for x86 can be a very remunerative proposal for a company that is either trying to keep Oracle licensing costs down or trying to get out from under an Oracle licensing audit scrutiny to be compliant. However, understanding how Oracle licensing works can be like peeling back the layers of an onion. 

Most organizations choose VMware as their virtual platform market leader. But it’s safe to say that Oracle licensing is not very VMware-friendly. You are generally required to license every core of every server in the cluster. This means not only licensing all the cores on the server you are running the VM (Virtual Machine) on, but all the cores on any server that the VM could potentially be migrated to (think vMotion). 

The best way to overcome this licensing issue is by creating hard partitions.  The partition will help to segment the CPU core as per your core license.

What is partitioning? 

“Partitioning” occurs when the CPUs on a server are separated into individual sections where each section acts as a separate system. Sometimes this is called “segmenting.” There are many hardware and software virtualization technologies available that deliver partitioning capabilities, with varying degrees of resource allocation flexibility.

There are two types of partitions 

1. Soft partition
2. Hard partition

Soft partition :

Soft partitioning segments the operating system using OS resource managers. The operating system limits the number of CPUs where an Oracle database is running by creating areas where CPU resources are allocated to applications within the same operating system. This is a flexible way of managing data processing resources since the CPU capacity can be changed fairly easily, as an additional resource is needed. 

Hard partition :

Hard partitioning physically segments a server, by taking a single large server and separating it into distinct smaller systems. Each separated system acts as a physically independent, self-contained server, typically with its own CPUs, operating system, separate boot area, memory, input/output subsystem,   and network resources.

For more details refer : https://www.oracle.com/a/ocom/docs/linux/ol-kvm-hard-partitioning.pdf

Let’s assume that you own 1 processor license for Oracle Database Enterprise Edition, and it's running it on a single socket 8-core server that is running Oracle VM for x86. The core multiplier for Intel Xeon chips is .5 and you own 1 processor license. This equals out to 2 cores. If you have more cores available on the server than what you’re using, then you can implement hard partitioning in Oracle VM for x86. This restricts your database VM to specific vCPUs (Virtual CPUs) and does not allow it to go beyond those limits even though more cores are technically available for use.

NOTE: In the diagrams below, I’m assuming Intel’s HyperThreading technology is being used. This creates two “threads” per core that each appears as a vCPU to Oracle VM for x86. It's safe to say that for every core, you get 2 vCPUs.

you should choose vCPUs that align on core boundaries as much as possible when you configure the partition. In other words, don’t pick vCPU0,2,4 and 6 from cores 0,1,2 and 3 respectively and think you’re only using 2 cores. Even though that may represent 2 cores worth of processing power, to Oracle it is considered to be 4 cores and they will expect you to be licensed as such! Here’s the wrong way to do it:

                            

                                                         Figure 1: Wrong way of pinning vcpu's

Below would be the proper way to pin your vCPUs to stay within core boundaries more effectively:

                                                   Figure 2: Correct way of pinning vcpu's

It's important to know just because we pinned the Vcpus, there is no guarantee that other VMs cant use those very same VCPUs . Assume that we have pinned and non-pinned VMs, the non-pinned VMs could potentially stray onto the pinned VMs' VCPUs and caused unintended performance issues. To avoid this, pin the database VM to its VCPUs and then pin all other VMs to the remaining VCPUs to segregate them. 

Here is the proper way to perform this pinning :

In this article, I will illustrate how to perform hard partitioning.

####### lscpu

[root@KVM120 ~]# lscpu
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              64
On-line CPU(s) list: 0-63
Thread(s) per core:  2
Core(s) per socket:  16
Socket(s):           2
NUMA node(s):        2
Vendor ID:           GenuineIntel
BIOS Vendor ID:      Intel(R) Corporation
CPU family:          6
Model:               85
Model name:          Intel(R) Xeon(R) Gold 6226R CPU @ 2.90GHz
BIOS Model name:     Intel(R) Xeon(R) Gold 6226R CPU @ 2.90GHz
Stepping:            7
CPU MHz:             1199.909
BogoMIPS:            5800.00
Virtualization:      VT-x
L1d cache:           32K
L1i cache:           32K
L2 cache:            1024K
L3 cache:            22528K
NUMA node0 CPU(s):   0-15,32-47
NUMA node1 CPU(s):   16-31,48-63
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single intel_ppin ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts hwp_epp pku ospke avx512_vnni md_clear flush_l1d arch_capabilities
[root@KVM120 ~]#

Understand the current CPU on the hypervisor

On a server running Oracle Linux KVM, you can run the lscpu command to print out the basic CPU configuration of the server hardware. As per this current architecture, we have 6 CPU's and cpu numbering starting with 0.

#### KVM cpu info 
[root@kvm01 ~]# lscpu
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              6
On-line CPU(s) list: 0-5
Thread(s) per core:  1
Core(s) per socket:  6
Socket(s):           1
NUMA node(s):        1
Vendor ID:           GenuineIntel
CPU family:          6
Model:               165
Model name:          Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz
Stepping:            2
CPU MHz:             2592.002
BogoMIPS:            5184.00
Virtualization:      VT-x
Hypervisor vendor:   KVM
Virtualization type: full
L1d cache:           32K
L1i cache:           32K
L2 cache:            256K
L3 cache:            12288K
NUMA node0 CPU(s):   0-5
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid tsc_known_freq pni pclmulqdq vmx ssse3 cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single tpr_shadow flexpriority fsgsbase avx2 invpcid rdseed clflushopt md_clear flush_l1d arch_capabilities
[root@kvm01 ~]#

Next step is to check the running vm that we need to pin the cpu.

[root@kvm01 ~]# virsh --readonly list
 Id   Name            State
-------------------------------
 1    oel7-test-tem   running

[root@kvm01 ~]#

Now we need to check vm is pinned to CPU or not , also using this virsh command which CPUs are allocated to the server VM.

[root@kvm01 ~]#  virsh --readonly vcpuinfo oel7-test-tem --pretty
VCPU:           0
CPU:            0
State:          running
CPU time:       68.0s
CPU Affinity:   0-5 (out of 6)

VCPU:           1
CPU:            2
State:          running
CPU time:       49.2s
CPU Affinity:   0-5 (out of 6)

[root@kvm01 ~]#

As per this example, the virtual machine is configured with 2 vCPUs and both can span from thread/core 0 until thread/core 5 (out of 6); so, the virtual CPUs for this virtual machine are not pinned to physical threads/cores.

Configuring Hard Partitioning

To perform this CPU pinning we need to install olvm-vmcontrol utility

The recommended method is to install this olvm-control on OLVM hosted server. Please refer to my OLVM engine installation blog: https://chanaka-dbhelp.blogspot.com/2022/08/olvm-oracle-linux-virtualization.html , This article will help you to set up the engine.

########## install olvm-vmcontrol
Note: We need to installed this seperatly or in olvm engine hosted machine.

dnf install olvm-vmcontrol -y

[root@kvm02 ~]# dnf install olvm-vmcontrol -y
Oracle Linux 8 Gluster Appstream (x86_64)                                                                                           37 kB/s | 3.2 kB     00:00
Oracle Linux 8 BaseOS Latest (x86_64)                                                                                               65 kB/s | 3.6 kB     00:00
Oracle Linux 8 BaseOS Latest (x86_64)                                                                                              9.4 MB/s |  50 MB     00:05
Oracle Linux 8 Application Stream (x86_64)                                                                                          71 kB/s | 3.9 kB     00:00
Oracle Linux 8 Application Stream (x86_64)                                                                                         9.1 MB/s |  38 MB     00:04
Latest oVirt 4.4 Release (x86_64)                                                                                                   33 kB/s | 3.0 kB     00:00
oVirt 4.4 Extra (x86_64)                                                                                                            49 kB/s | 3.0 kB     00:00
Latest Unbreakable Enterprise Kernel Release 6 for Oracle Linux 8 (x86_64)                                                          42 kB/s | 3.0 kB     00:00
Oracle Linux 8 KVM Application Stream (x86_64)                                                                                      45 kB/s | 3.2 kB     00:00
Oracle Linux 8 KVM Application Stream (x86_64)                                                                                     1.7 MB/s | 318 kB     00:00
Dependencies resolved.
===================================================================================================================================================================
 Package                                         Architecture                    Version                                  Repository                          Size
===================================================================================================================================================================
Installing:
 olvm-vmcontrol                                  noarch                          4.4.1-1.1.el8                            ovirt-4.4                           36 k
Installing dependencies:
 java-ovirt-engine-sdk4                          noarch                          4.4.6-1.el8                              ovirt-4.4                          4.4 M

Transaction Summary
===================================================================================================================================================================
Install  2 Packages

Total download size: 4.4 M
Installed size: 5.6 M
Downloading Packages:
(1/2): olvm-vmcontrol-4.4.1-1.1.el8.noarch.rpm                                                                                      24 kB/s |  36 kB     00:01
(2/2): java-ovirt-engine-sdk4-4.4.6-1.el8.noarch.rpm                                                                               1.8 MB/s | 4.4 MB     00:02
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                              1.8 MB/s | 4.4 MB     00:02
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                                           1/1
  Installing       : java-ovirt-engine-sdk4-4.4.6-1.el8.noarch                                                                                                 1/2
  Installing       : olvm-vmcontrol-4.4.1-1.1.el8.noarch                                                                                                       2/2
  Running scriptlet: olvm-vmcontrol-4.4.1-1.1.el8.noarch                                                                                                       2/2
  Verifying        : java-ovirt-engine-sdk4-4.4.6-1.el8.noarch                                                                                                 1/2
  Verifying        : olvm-vmcontrol-4.4.1-1.1.el8.noarch                                                                                                       2/2

Installed:
  java-ovirt-engine-sdk4-4.4.6-1.el8.noarch                                           olvm-vmcontrol-4.4.1-1.1.el8.noarch

Complete!
[root@kvm02 ~]#

To execute this we need to export the OLVM password as an export parameter eg : export OLVMUTIL_PASS=Password

Execution error

I got the error while executing getcpu commands , This error was due to a certificate issue.

[root@kvm02 ~]# olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c getvcpu 
Oracle Linux Virtualization Manager VM Control Utility 4.4.1-1.1
Password:
Error connecting to manager.  Please check manager_hostname, username, password and keystore.
Full error: Failed to send request
Caused by: org.ovirt.engine.sdk4.Error: Failed to parse JSON response
Caused by: javax.net.ssl.SSLException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty

Solution

There is an easy way to execute this without the certificate validation bypass by using the flag -f

-f InsecureConnection Append the -f flag to connect to the OLVM Manager without checking for Keystore file and JDK Version. The olvm-vmcontrol utility expects the keystore to be in jks format. So appending the -f flag is a workaround to creating a jks keystore.

[root@kvm02 SSL_CERT]# olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c getvcpu -f
Oracle Linux Virtualization Manager VM Control Utility 4.4.1-1.1
Password:
Connected to Oracle Linux Virtualization Manager 4.4.8.6-1.0.11.el8
Getting vcpu pinning ...
No CPU pinning is configured
[root@kvm02 SSL_CERT]#

This command returns the output for get and shows that VM hard partition is not configured

Allocation of CPUs

We can use olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c setvcpu -s 0,1 -e -f command to pin to cpu As per this example we are pinning to vm to use cpu 0 and cpu 1.

Note: Make sure to reboot the server, then only it will affect the CPU setting.

olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c setvcpu -s 0,1 -e -f
 
[root@kvm02 SSL_CERT]# olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c setvcpu -s 0,1 -e -f
Oracle Linux Virtualization Manager VM Control Utility 4.4.1-1.1
Connected to Oracle Linux Virtualization Manager 4.4.8.6-1.0.11.el8
Setting vcpu pinning ...
Setting VM's "Start Running On: Specific Host(s)" to host kvm01
Trying to pin virtual cpu # 0
Trying to pin virtual cpu # 1
Retrieving vcpu pinning to confirm it has been set...
No CPU pinning is configured

NOTE: if the VM is running you must now stop and then start the VM from the Oracle Linux Virtualization Manager in order for CPU pinning changes to take effect.
NOTE: a restart or a reboot of the VM is not sufficient to put CPU pinning changes into effect.

Validation

Execute getcpu command to validate the server cpu setting are correct.

olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c getvcpu -f -e

 olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c getvcpu -f -e

[root@kvm02]# olvm-vmcontrol -m kvm02.local.com -u admin@internal -v oel7-test-tem -c getvcpu -f -e
Oracle Linux Virtualization Manager VM Control Utility 4.4.1-1.1
Connected to Oracle Linux Virtualization Manager 4.4.8.6-1.0.11.el8
Getting vcpu pinning ...
vcpu 0 pinned to cpuSet[0,1]
vcpu 1 pinned to cpuSet[0,1]
[root@kvm02 SSL_CERT]#

Conclusion

Many organizations suffer from oracle licensing when it comes to virtual platforms. There are many features that come with virtualization that enables the creation of a database server within minutes, due to this flexibility there high chance that the organization violates this oracle licensing policy. 

Oracle licensing is not that supportive for platforms like VMware Esxi. To overcome this we can use hard partitioning. This feature enables organizations to stay within the oracle licensing boundary and avoid unnecessary performance disturbances that can be caused by VCPU sharing. 

Configure KVM Hypervisor with OLVM (Oracle Linux Virtual Manager) - Part 2/5

 

                                  

Intro

acronym:

OLVM - Oracle Linux Virtual Manager

KVM   - Kernel-based Virtual Machine

OVM   - Oracle Virtual Manager

ODA    - Oracle Data Appliance 

OLVM (Oracle Linux Virtual Manager) elevated the KVM (kernel-based virtual Machine)  management processes and reduced administration overhead.  As Oracle is moving out of OVM (Oracle Virtual Manager), customers who are using OVM as their virtualized platform need to plan the OLVM journey. Many small-medium scale businesses are still using virtualized ODA and hosted the VMS on top of ODA.  

I think now is the right time to move out of OVM to Oracle KVM.  KVM hypervisors are much more stable than OVM. Oracle's future plans are combined with open-source virtualization. Also, there are many more features than the OVM. The below-mentioned table demonstrates the enhancements OLVM has over the old OVM platform.

Virtualization technology still has a high demand for managing on-prem databases on top of Oracle KVM.   Also, I have listed down some of the key features of OLVM.

Key features of OLVM

• Live VM migration between hosts
• Oracle Enterprise Manager Integration (OEM)
• CPU Pinning Capabilities
• VM High Availability
• Virtual Appliances & Templates (ovf/ova support)
• Snapshotting of existing VMs. This is an additional feature from OVM
• Role-based User access
• Web-based User Interface (UI)
• Representation State Transfer (REST)
• Application Programming Interface (API)

Integrate KVM with OLVM

In this article, I will cover how to add pre-existing KVM hypervisor to the OLVM engine. I have shared the oracle note explaining how to prepare the KVM.

https://docs.oracle.com/en/virtualization/oracle-linux-virtualization-manager/getstart/getstarted-manager-install.html#manager-prep-kvm

OL8 server needs to enable the ol8 repo to integrate KVM with OLVM.  Make sure you can have internet access on these hosts to access the repo. Once you configure the KVM then can remove the internet connection from KVM hypervisors.

OLVM (Oracle Linux Virtualization Manager) - Change hostname

 

Intro

OLVM (Oracle Linux Virtual Manager) is the single point of GUI (web console) that enables system engineers to manage multiple KVMs, Vms, Storage domains and etc ... .  Also note that Oracle Linux KVM is the same hypervisor used in the Oracle Cloud. To get more insight about OCI cloud infrastructure virtualization I shared the below mention pdf to get more understanding about the KVM used in Oracle Cloud: https://www.oracle.com/a/ocom/docs/olvm-datasheet-nov2019.pdf .  Oracle OVM era is over, an alternative to OVM is KVM, offered under Oracle Linux Virtualization Manager (OLVM).

I have shared the oracle documentation link which has all the details related to virtualization.

Oracle Linux Virtualization Manager - Books

Also, Oracle KVM and OLVM come up with many benefits. A few advantages are mentioned below.

• Complete server virtualization and management solution with zero license cost.

• Single software distribution for Oracle Linux OS or Oracle Linux KVM.

• Speeds application deployment with Oracle Virtual Appliances.

• Hard Partitioning support enables efficient Oracle application software licensing.

• Full Stack Management with Oracle Enterprise Manager.

• Path to Oracle Cloud Infrastructure with a common hypervisor

In this article, I will cover how to change the hostname of the OLVM server. This may be required if you need to move OLVM to a different data center with new hostname.