feat: Add 2-node quorum support for RustFS cluster

Configure RustFS erasure coding to allow cluster operation with 2 out
of 3 nodes (EC:1 = 1 parity drive).

Changes:
- Add rustfs_storage_class_standard variable (default: EC:1)
- Add RUSTFS_STORAGE_CLASS_STANDARD to cluster config template
- Add config tag to config task for targeted updates

Apply config changes with:
  ansible-playbook -i inventory/ plays/install-rustfs.yml --tags config

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

ansible/roles/rustfs/defaults/main.yml

@@ -16,3 +16,7 @@ rustfs_secret_key: "rustfsadmin"
 rustfs_console_enable: true
 rustfs_obs_logger_level: "error"
 
+# Erasure coding - EC:1 allows 2-node quorum (1 parity drive)
+# With 3 nodes, this means the cluster can operate with 2 nodes up
+rustfs_storage_class_standard: "EC:1"
+

ansible/roles/rustfs/tasks/main.yml

@@ -80,6 +80,9 @@
     src: rustfs.cluster.j2
     dest: "{{ rustfs_config_file }}"
   notify: Restart rustfs
+  tags:
+    - config
+    - rustfs-config
 
 - name: Create RustFS systemd service
   template:

ansible/roles/rustfs/templates/rustfs.cluster.j2

@@ -7,3 +7,5 @@ RUSTFS_CONSOLE_ADDRESS=":{{ rustfs_console_port }}"
 RUSTFS_CONSOLE_ENABLE={{ rustfs_console_enable | lower }}
 RUSTFS_OBS_LOGGER_LEVEL={{ rustfs_obs_logger_level }}
 RUSTFS_OBS_LOG_DIRECTORY="{{ rustfs_log_dir }}/"
+# Erasure coding for 2-node quorum support
+RUSTFS_STORAGE_CLASS_STANDARD="{{ rustfs_storage_class_standard }}"