|
| 1 | +.. Licensed to the Apache Software Foundation (ASF) under one |
| 2 | + or more contributor license agreements. See the NOTICE file |
| 3 | + distributed with this work for additional information# |
| 4 | + regarding copyright ownership. The ASF licenses this file |
| 5 | + to you under the Apache License, Version 2.0 (the |
| 6 | + "License"); you may not use this file except in compliance |
| 7 | + with the License. You may obtain a copy of the License at |
| 8 | + http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + Unless required by applicable law or agreed to in writing, |
| 10 | + software distributed under the License is distributed on an |
| 11 | + "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 12 | + KIND, either express or implied. See the License for the |
| 13 | + specific language governing permissions and limitations |
| 14 | + under the License. |
| 15 | +
|
| 16 | +
|
| 17 | +Adding Clusters |
| 18 | +--------------- |
| 19 | + |
| 20 | +Additional clusters can be added at any time to add a new set of hosts. |
| 21 | +For requirements and instructions, see :ref:`adding-a-cluster`. |
| 22 | + |
| 23 | + |
| 24 | +CloudStack DRS |
| 25 | +-------------- |
| 26 | +DRS is a process that can rebalance instances across cluster as per the configured algorithm. |
| 27 | +There are two algorithms available: |
| 28 | + |
| 29 | +#. **Condensed** spread instances across hosts as densely as possible. |
| 30 | + This is useful for reducing the number of hosts used. This is the default algorithm. |
| 31 | +#. **Balanced** spread instances across hosts as evenly as possible. |
| 32 | + This is useful for reducing the load on each host. |
| 33 | + |
| 34 | +Configuring DRS |
| 35 | +~~~~~~~~~~~~~~~ |
| 36 | +Following are the configuration parameters for DRS. |
| 37 | + |
| 38 | +.. list-table:: DRS related cluster parameters |
| 39 | + :header-rows: 1 |
| 40 | + |
| 41 | + * - Parameter |
| 42 | + - Default |
| 43 | + - Description |
| 44 | + * - ``drs.plan.expire.interval`` |
| 45 | + - `30` |
| 46 | + - The interval in days after which the DRS events will be cleaned up. |
| 47 | + * - ``drs.automatic.enable`` |
| 48 | + - `false` |
| 49 | + - Enable/disable automatic DRS on a cluster. |
| 50 | + * - ``drs.automatic.interval`` |
| 51 | + - `60` |
| 52 | + - The interval in minutes after which a periodic background thread will schedule DRS for a cluster. |
| 53 | + * - ``drs.iterations`` |
| 54 | + - `0.2` |
| 55 | + - The maximum number of VM migrations to perform for DRS. This is defined as a percentage (as a value between 0 and 1) of total number of workloads. The minimum number of iterations per round will be 1 and maximum will be equal to the total number of workloads in a cluster. |
| 56 | + * - ``drs.algorithm`` |
| 57 | + - `condensed` |
| 58 | + - DRS algorithm to execute on the cluster. Available algorithms - `condensed`, `balanced`. |
| 59 | + * - ``drs.level`` |
| 60 | + - `5` |
| 61 | + - The level of DRS to perform on cluster. This determines the amount of imbalance allowed in the cluster. `10` means no imbalance is allowed and `1` means some imbalance is allowed |
| 62 | + * - ``drs.metric`` |
| 63 | + - `cpu` |
| 64 | + - The cluster imbalance metric to use when considering the imbalance in cluster. Possible values are memory, cpu, or both (cpu AND memory crosses the threshold). |
| 65 | + |
| 66 | +.. note:: |
| 67 | + Scope of ``drs.plan.expire.interval`` is global and for rest is cluster level. |
| 68 | + |
| 69 | +Executing manual DRS on a cluster |
| 70 | +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 71 | +DRS can also be manually executed for a cluster. |
| 72 | + |
| 73 | +Follow these steps to execute DRS for a cluster using the UI: |
| 74 | + |
| 75 | +#. Configure DRS parameters as per the requirement. |
| 76 | + |drs-cluster-settings.png| |
| 77 | +#. Open DRS tab for the cluster. |
| 78 | + |drs-cluster-tab.png| |
| 79 | +#. Select the iteration percentage to execute for the cluster. |
| 80 | +#. Click on `Generate DRS Plan` button. A modal will appear showing migrations |
| 81 | + for that cluster as per the configured algorithm. |
| 82 | + |drs-plan.png| |
| 83 | +#. Validate the migrations, and click on `Execute` button to execute the |
| 84 | + suggested migrations. |
| 85 | + |
| 86 | + |
| 87 | +.. note:: |
| 88 | + Only one DRS process can run for a cluster at a time. If you try to run DRS while another |
| 89 | + DRS process is running, the second process will fail. |
| 90 | + |
| 91 | + |
| 92 | +.. |drs-cluster-settings.png| image:: /_static/images/drs-cluster-settings.png |
| 93 | + :alt: DRS settings for a cluster. |
| 94 | + |
| 95 | +.. |drs-cluster-tab.png| image:: /_static/images/drs-cluster-tab.png |
| 96 | + :alt: DRS tab for a cluster. |
| 97 | + |
| 98 | +.. |drs-plan.png| image:: /_static/images/drs-plan.png |
| 99 | + :alt: DRS plan for a cluster. |
0 commit comments