VMware ESXI/VCenter

Zeroed

"zeroed" refers to the process of initializing the storage space with zeros (null or empty data) (basically zeros are like formatting the disk)

Storage Vmotion

- migrating only the storage of the virtual machine from one storage device to another (while the virtual machine is still powered on)

Datastore with APD (All Paths Down)

- occurs when all paths to a storage device are lost or become unavailable, but the ESXi host has not yet determined whether the condition is permanent (so APD is temporary).

DRS (Distributed Resource Scheduler)

- this looks at which ESXI server has more or less resources (CPU/memory load) and moves the virtual machines around based on that (Basically load balancing the VM's to ESXI servers) You need a cluster to use DRS (only vmotion can be used without a cluster)

VMware vSphere

A comprehensive platform that includes ESXi as its hypervisor, but it also incorporates additional components such as vCenter Server, vSAN (Virtual Storage Area Network), vMotion for live migration of virtual machines, and more.

RDM Disk

Allows you to connect a physical disk on your server to a VM without creating a virtual disk

Q: with vsphere, if you take a snapshot of a virtual machine and revert back to that snapshot, then when you delete the snapshot, does the data from the snapshot consolidate to the virtual machines harddrive?

Answer: Yes, when you delete a snapshot in vSphere, the data from the snapshot is consolidated into the virtual machine's hard drive. Here is an overview of the process: 1) Snapshot Creation: When you take a snapshot of a virtual machine, a new set of files is created to capture the state of the VM at that specific point in time. This includes the virtual machine's disk, memory, and configuration files. 2) Snapshot Changes: As the virtual machine continues to run and changes are made, new data is written to the snapshot files rather than the original virtual machine disk files. This allows the snapshot to capture the changes without modifying the original data. 3) Snapshot Deletion: When you decide to delete a snapshot, the changes that were stored in the snapshot files automatically get merged or consolidated back into the original virtual machine disk files. 4) Consolidation Process: The consolidation process involves taking the changes stored in the snapshot and merging them with the base virtual machine disk files. This process ensures that the virtual machine's disk reflects the data captured in the snapshot.

OVF = Open Virtual Format OVA = Open Virtual Appliance

By exporting a virtual machine as an OVF file, you create a portable package that can be imported and run on other virtualization platforms, including Oracle VirtualBox, Microsoft Hyper-V, etc (you can also use OFV files to transfer a virtual machine from one ESXI host to a different one

vCenter

Central management solution that can manage all your ESXi hosts in a single view.

Fault Tolerance

Creates a mirror copy of a virtual machine in another host which is always powered on In the case of VMware Fault Tolerance (FT), if one of the ESXi hosts hosting a virtual machine goes down, the mirrored copy of that virtual machine on another ESXi host takes over without any downtime (as compared to High Availability where there is downtime). Also, for fault tolerance, you need to be using shared storage (SAN/NAS) for the virtual machines When there is an issue with the primary virtual machine, then the secondary machine will become the primary machine with no downtime

Host profiles

Host profiles are used to establish and enforce a consistent configuration standard across multiple ESXi hosts. This ensures that hosts have the same settings for networking, storage, security, and other configurations. A host profile in VMware vSphere acts like a template or blueprint for ESXi hosts.

Vsphere High Availability

In case an ESXI has a failure or shuts off (unplug power from ESXI host), then any virtual machines on that ESXI host will be automatically restarted (rebooting) on another ESXI host for vsphere high avaibility to work, your virtual machines need to be using shared storage

Resource Shares

Resource shares are used to determine the proportional allocation of resources during periods of contention. VMs or resource pools with higher share values receive a larger share of available resources. Resource shares are beneficial in scenarios where certain VMs or resource pools need higher priority access to resources. For example, critical applications may be assigned higher shares to ensure they receive sufficient resources during contention.

Thick Provisioned, Eagerly Zeroed:

Similar to thick provisioned lazily zeroed, but with eager zeroed, the entire space is zeroed out during the initial disk creation.

remember

The .vmdk stores the harddrive of the Virtual Machine (virtual hard drive)

Uplinks

The physical network adapter used by an ESXI host to communicate to the physical network Its best practice to have 2 physical network adapters in your host for redundancy.

Thin Provisioned

Thin provisioning allocates storage space on-demand. The virtual disk starts small and grows as the virtual machine's data increases.

remember

To remote into an ESXI machine (for example say its at a datacenter and you cant go there in person, its too far) you would have to SSH into the ESXI Shell (make sure ESXI shell is enabled)

Vapp

a container for grouping and managing multiple virtual machines (VMs) together as a single application entity in VMware vSphere (For example, VMs within a vApp can be powered on or off together and you can select which VMs get shut off first, second, etc and turned on first, second, etc .).

VM Snapshot

a point-in-time image of the state of a virtual machine, capturing its configuration, disk, and memory contents at a specific moment. Snapshots are used when you want to make a change to the VMs operating system and aren't sure of the outcome (windows update, application update, registry change, etc)

VSphere Client

administrative interface to access VMware hosts

resource pool

allows administrators to define and manage the allocation of CPU and memory resources among a group of virtual machines (VMs) within a host or cluster

vCenter Converter

allows you to convert physical machines into virtual (P2V) machines w/o any downtime The tool allows you to create a virtualized version of your existing (or remote) Windows 10,Linux, Mac, etc operating system, which can then be run on a virtualization platform such as VMware vSphere or other compatible hypervisors (Hyperv, KVM) The tool can also do virtual to virtual (V2V) so it moves your virtual machine from one virtualization environment to another For example, if you have a virtual machine running on VMware Workstation or Oracle VirtualBox and you want to migrate it to a VMware vSphere environment, you can use vCenter Converter for this purpose. (You could export the OVA file and import it into Vsphere but that takes a lot of time. Instead you can just use vCenter converter

Vmotion

allows you to migrate a virtual machine (that's powered on) from a host to another host Vmotion needs a vMotion vmkernel (once you have this kernel, vMotion will be enabled and you can start migrating machines and/or using DRS) The hosts using vMotion also need to have shared storage (NAS/SAN) so that when u transfer a virtual machine to another host, that host already has the data of the machine from the shared storage

Dedicated Failover Host

an ESXi host that is kept in a standby state with no virtual machines running under normal conditions. Its primary purpose is to be available to take on the virtual machines from other hosts within the same HA cluster in the event of a host failure.

Cluster

container that holds all your hosts/virtual machines and can apply specific rules to that container

.vmx file

file stores the information about the virtual machines hardware (amount of ram, how big the hard drive is, CPU, etc). The .vmx is a configuration file.

Proactive High Availability (HA)

helps to avoid virtual machine downtime by detecting hardware failures of the ESXI host ahead of time by using predictive analysis (needs DRS to be enabled on the cluster)

ESXI

just the the hypervisor product responsible for running the virtual machines. Vsphere is basically the full virtualization platform that includes other tools/services for a company

Storage DRS

migrates a virtual machines datastore to another datastore (could be the datastore has little free space left so DRS will migrate the storage of a virtual machine to another datastore)

Vrealize

monitors your environment and detects if there's any problem (analyzes data), (best for environments with more than 6 hosts, not good for environments with less than 6 hosts

Data Store with PDL

occurs when the storage subsystem or the ESXi host determines that a device has been permanently lost or is no longer accessible

VMware tools

part of an ESXI server that should be installed on a virtual machine to pull accurate information about the machine

vNetwork distributed switch

provides a consistent network for virtual machines as they migrate across multiple hosts (distributed switches are created at the Vcenter level) Virtual machines connected to a vDS maintain a consistent network configuration, including port groups, VLANs, and other network policies, regardless of the ESXi host they are running on

VM-to-VM anti-affinity

run VMs on different hosts This is important because say you have two domain controllers or two mail servers right. You don't want both of those servers on the same host because if the host goes down, you lose both of your servers.

VM-to-VM Affinity

run VMs on the same host Another example in terms of affinity is say you have say an App Server VM that uses an Oracle Database VM to store data. You would want both of those VMs on the same host because the App Server needs the Oracle database to function (but it is recommended to just have the app server talk to the oracle database over the network and still have them on 2 different hosts because its best practice to dedicate one host to a particular server/function)

Hypervisor

server that hosts a virtual machine on top of it (ESXI)

Thick Provisioned, Lazily Zeroed

space is allocated and zeroed on demand. The zeros are written to the disk as the data is written

Vsphere Update Manager

used to update/patch ESXI hosts with critical security updates, bug fixes, etc for their Vmware versions (it updates the ESXI hosts vmware versions as well so update the version from 6.0 to 7.0 or 7.0 to 8.0) If you have High Availability (HA) enabled, Update Manager will smoothly update one ESXi server at a time. It moves your virtual machines to a different server while the original one is being updated.

vNetwork Standard Switch

virtual switch configuration for a single host (whenever you install ESXI on a server, they automatically create a standard switch, "VM Network") Configuration is local to each ESXi host. If you have multiple hosts, you need to configure standard switches on each host separately.

Host Isolation

when an ESXI host cannot communicate to the network anymore, but the host and the virtual machines are still powered on

Maintenance mode

will migrate the virtual machines on the ESXI to another host (ESXI), while you perform maintenance on the ESXI machine. (this will only work if you have HA enabled)