[DPE-4859] Make cloud-init optional

README.md

@@ -26,37 +26,44 @@ Bootstrap a [lxd controller](https://juju.is/docs/olm/lxd#heading--create-a-cont
 juju add-model opensearch
 ```
 
-Configure the system settings required by [OpenSearch](https://opensearch.org/docs/latest/install-and-configure/install-opensearch/index/),
-we'll do that by creating and setting a [`cloudinit-userdata.yaml` file](https://juju.is/docs/olm/juju-model-config) on the model. 
-As well as setting some kernel settings on the host machine.
+Configure the system settings required by [OpenSearch](https://opensearch.org/docs/latest/install-and-configure/install-opensearch/index/).
+
+### Basic usage
+
+To deploy a single unit of OpenSearch with default configuration, use:
+
+```shell
+juju deploy opensearch --channel=2/edge
 ```
-cat <<EOF > cloudinit-userdata.yaml
-cloudinit-userdata: |
-  postruncmd:
-    - [ 'echo', 'vm.max_map_count=262144', '>>', '/etc/sysctl.conf' ]
-    - [ 'echo', 'vm.swappiness=0', '>>', '/etc/sysctl.conf' ]
-    - [ 'echo', 'net.ipv4.tcp_retries2=5', '>>', '/etc/sysctl.conf' ]
-    - [ 'echo', 'fs.file-max=1048576', '>>', '/etc/sysctl.conf' ]
-    - [ 'sysctl', '-p' ]
-EOF
 
+### LXD setup
+
+If you are using LXD as the backend for Juju, then most of the sysctl parameters need to be set manually on the hypervisor:
+
+```shell
 sudo tee -a /etc/sysctl.conf > /dev/null <<EOT
 vm.max_map_count=262144
 vm.swappiness=0
-net.ipv4.tcp_retries2=5
 fs.file-max=1048576
 EOT
 
 sudo sysctl -p
-
-juju model-config --file=./cloudinit-userdata.yaml
 ```
 
-### Basic Usage
-To deploy a single unit of OpenSearch using its default configuration.
+### Customise system settings with cloud-init
+
+Optionally, system can be configured with different cloud-init values than set by default.
+We'll do that by creating and setting a [`cloudinit-userdata.yaml` file](https://juju.is/docs/olm/juju-model-config) on the model. 
 
 ```shell
-juju deploy opensearch --channel=2/edge
+cat <<EOF > cloudinit-userdata.yaml
+cloudinit-userdata: |
+  postruncmd:
+    - [ 'echo', 'net.ipv4.tcp_retries2=2', '>>', '/etc/sysctl.conf' ]
+    - [ 'sysctl', '-p' ]
+EOF
+
+juju model-config --file=./cloudinit-userdata.yaml
 ```
 
 ## Relations / Integrations
@@ -73,6 +80,7 @@ juju integrate opensearch data-integrator
 ```
 
 ### Large deployments:
+
 Charmed OpenSearch also allows to form large clusters or join an existing deployment, through the relations:
 - `peer-cluster`
 - `peer-cluster-orchestrator`
@@ -109,11 +117,13 @@ juju remove-relation opensearch self-signed-certificates
 **Note:** The TLS settings shown here are for self-signed-certificates, which are not recommended for production clusters. The Self Signed Certificates Operator offers a variety of configuration options. Read more on the TLS Certificates Operator [here](https://charmhub.io/self-signed-certificates).
 
 ## Security
+
 Security issues in the Charmed OpenSearch Operator can be reported through [LaunchPad](https://wiki.ubuntu.com/DebuggingSecurity#How%20to%20File). Please do not file GitHub issues about security issues.
 
 ## Contributing
 
 Please see the [Juju SDK docs](https://juju.is/docs/sdk) for guidelines on enhancements to this charm following best practice guidelines, and [CONTRIBUTING.md](https://github.com/canonical/opensearch-operator/blob/main/CONTRIBUTING.md) for developer guidance.
 
 ## License
+
 The Charmed OpenSearch Operator is free software, distributed under the Apache Software License, version 2.0. See [LICENSE](https://github.com/canonical/opensearch-operator/blob/main/LICENSE) for more information.

tests/integration/helpers.py

@@ -39,12 +39,6 @@
 MODEL_CONFIG = {
     "logging-config": "<root>=INFO;unit=DEBUG",
     "update-status-hook-interval": "5m",
-    "cloudinit-userdata": """postruncmd:
-        - [ 'sysctl', '-w', 'vm.max_map_count=262144' ]
-        - [ 'sysctl', '-w', 'fs.file-max=1048576' ]
-        - [ 'sysctl', '-w', 'vm.swappiness=0' ]
-        - [ 'sysctl', '-w', 'net.ipv4.tcp_retries2=5' ]
-    """,
 }