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new e54a5ec Documentation related to VM and Volume allocators (#499)
e54a5ec is described below
commit e54a5ec2fd5307d29a642e25b3b73cced9fb24f4
Author: Manoj Kumar <manojkr.it...@gmail.com>
AuthorDate: Fri May 16 17:37:18 2025 +0530
Documentation related to VM and Volume allocators (#499)
---
source/adminguide/index.rst | 1 +
source/adminguide/vm_volume_allocators.rst | 80 ++++++++++++++++++++++++++++++
2 files changed, 81 insertions(+)
diff --git a/source/adminguide/index.rst b/source/adminguide/index.rst
index 720e0cd..3a3d22b 100644
--- a/source/adminguide/index.rst
+++ b/source/adminguide/index.rst
@@ -140,6 +140,7 @@ Managing VM and Volume Allocation
host_and_storage_tags
arch_types
+ vm_volume_allocators
Managing Networks and Traffic
-----------------------------
diff --git a/source/adminguide/vm_volume_allocators.rst
b/source/adminguide/vm_volume_allocators.rst
new file mode 100644
index 0000000..91ea10e
--- /dev/null
+++ b/source/adminguide/vm_volume_allocators.rst
@@ -0,0 +1,80 @@
+.. Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information#
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+ http://www.apache.org/licenses/LICENSE-2.0
+ Unless required by applicable law or agreed to in writing,
+ software distributed under the License is distributed on an
+ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ KIND, either express or implied. See the License for the
+ specific language governing permissions and limitations
+ under the License.
+
+
+VM and Volume Allocators
+======================
+
+Each Instance must be deployed in suitable deployment destination. Deployment
destination is set of recommended resources that you can choose for deploying
an instance.
+A deployment planner provides the suitable deployment destination that is
required for a instance.
+
+Allocators are used to figure out suitable host and storage pools for
deploying the Instance:
+
+#. VM Allocator
+#. Volume Allocator
+
+
+VM Allocator
+------------
+
+VM allocator returns suitable hosts in the cluster where you can deploy the
given instance. Various parameters e.g. CPU and
+RAM capacity, current state of the host are considered to decide the host.
+
+VM allocator supports following algorithms to select a host in the cluster:
+
+.. cssclass:: table-striped table-bordered table-hover
+
+============================= ========================
+Algorithm Description
+============================= ========================
+random Selects a host in the cluster randomly.
+firstfit Selects the first available host in the
cluster.
+userdispersing Selects the host running least instances for the
account, aims to spread out the instances belonging to a single user account.
+userconcentratedpod_random Selects the host randomly aiming to keep all
instances belonging to single user account in same pod.
+userconcentratedpod_firstfit Selects the first suitable host from a pod
running most instances for the user.
+firstfitleastconsumed Selects the first host after sorting eligible
hosts by least allocated resources (such as CPU or RAM).
+============================= ========================
+
+Use global configuration parameter:
+**vm.allocation.algorithm** to specify the algorithm that the Allocator must
use. By default it is configured to use "random" algorithm.
+
+
+Volme Allocator
+--------------
+
+Volume allocator returns suitable storage pools available in the cluster where
volumes of the given instance can be created.
+To decide the storage pools, it considers factors such as disk offering,
storage capactiy, availability scope etc.
+
+Volume allocator supports following algorithms to select a host in the cluster:
+
+.. cssclass:: table-striped table-bordered table-hover
+
+============================= ========================
+Algorithm Description
+============================= ========================
+random Selects a storage pool in the cluster
randomly.
+firstfit Selects the first available storage
pool in the cluster.
+userdispersing Selects the storage pool running least
instances for the account, aims to spread out the instances belonging to a
single user account.
+userconcentratedpod_random Selects the storage pool randomly aiming to
keep all instances belonging to single user account in same pod.
+userconcentratedpod_firstfit Selects the first suitable pool from a pod
running most instances for the user.
+firstfitleastconsumed Selects the first storage pool after sorting
eligible pools by least allocated resources.
+============================= ========================
+
+.. note::
+ Since 4.21.0, dedicated named configuration is provided for admin to
configure volume allocation algorithm.
+
+ **volume.allocation.algorithm**: random (default)
+
+ Before 4.21.0, **vm.allocation.algorithm** was used for both VM as well as
Volume allocation.
\ No newline at end of file
