Add configuration online update documentation

docs/config/src/common.yml

@@ -11,13 +11,21 @@
 - name: etcd_address
   type: string or array of strings
   type_ru: строка или массив строк
+  online: true
   info: |
     etcd connection endpoint(s). Multiple endpoints may be delimited by "," or
     specified in a JSON array `["10.0.115.10:2379/v3","10.0.115.11:2379/v3"]`.
     Note that https is not supported for etcd connections yet.
+
+    etcd connection endpoints can be changed online by updating global
+    configuration in etcd itself - this allows to switch the cluster to new
+    etcd addresses without downtime.
   info_ru: |
     Адрес(а) подключения к etcd. Несколько адресов могут разделяться запятой
     или указываться в виде JSON-массива `["10.0.115.10:2379/v3","10.0.115.11:2379/v3"]`.
+
+    Адреса подключения к etcd можно поменять на лету, обновив конфигурацию в
+    самом etcd - это позволяет переключить кластер на новые etcd без остановки.
 - name: etcd_prefix
   type: string
   default: "/vitastor"
@@ -31,5 +39,6 @@
 - name: log_level
   type: int
   default: 0
+  online: true
   info: Log level. Raise if you want more verbose output.
   info_ru: Уровень логгирования. Повысьте, если хотите более подробный вывод.

docs/config/src/make.js

@@ -14,6 +14,7 @@ const L = {
         toc_config: '[Configuration](../config.en.md)',
         toc_usage: 'Usage',
         toc_performance: 'Performance',
+        online: 'Can be changed online: yes',
     },
     ru: {
         Documentation: 'Документация',
@@ -28,6 +29,7 @@ const L = {
         toc_config: '[Конфигурация](../config.ru.md)',
         toc_usage: 'Использование',
         toc_performance: 'Производительность',
+        online: 'Можно менять на лету: да',
     },
 };
 const types = {
@@ -70,6 +72,8 @@ for (const file of params_files)
                 out += `- ${L[lang]['Default'] || 'Default'}: ${c.default}\n`;
             if (c.min !== undefined)
                 out += `- ${L[lang]['Minimum'] || 'Minimum'}: ${c.min}\n`;
+            if (c.online)
+                out += `- ${L[lang]['online'] || 'Can be changed online: yes'}\n`;
             out += `\n`+(c["info_"+lang] || c["info"]).replace(/\s+$/, '');
         }
         const head = fs.readFileSync(__dirname+'/'+file+'.'+lang+'.md', { encoding: 'utf-8' });

docs/config/src/network.yml

@@ -164,18 +164,21 @@
   type: sec
   min: 1
   default: 5
+  online: true
   info: Interval before attempting to reconnect to an unavailable OSD.
   info_ru: Время ожидания перед повторной попыткой соединиться с недоступным OSD.
 - name: peer_connect_timeout
   type: sec
   min: 1
   default: 5
+  online: true
   info: Timeout for OSD connection attempts.
   info_ru: Максимальное время ожидания попытки соединения с OSD.
 - name: osd_idle_timeout
   type: sec
   min: 1
   default: 5
+  online: true
   info: |
     OSD connection inactivity time after which clients and other OSDs send
     keepalive requests to check state of the connection.
@@ -186,6 +189,7 @@
   type: sec
   min: 1
   default: 5
+  online: true
   info: |
     Maximum time to wait for OSD keepalive responses. If an OSD doesn't respond
     within this time, the connection to it is dropped and a reconnection attempt
@@ -198,6 +202,7 @@
   type: ms
   min: 50
   default: 500
+  online: true
   info: |
     OSDs respond to clients with a special error code when they receive I/O
     requests for a PG that's not synchronized and started. This parameter sets
@@ -211,6 +216,7 @@
 - name: max_etcd_attempts
   type: int
   default: 5
+  online: true
   info: |
     Maximum number of attempts for etcd requests which can't be retried
     indefinitely.
@@ -220,6 +226,7 @@
 - name: etcd_quick_timeout
   type: ms
   default: 1000
+  online: true
   info: |
     Timeout for etcd requests which should complete quickly, like lease refresh.
   info_ru: |
@@ -228,6 +235,7 @@
 - name: etcd_slow_timeout
   type: ms
   default: 5000
+  online: true
   info: Timeout for etcd requests which are allowed to wait for some time.
   info_ru: |
     Максимальное время выполнения запросов к etcd, для которых не обязательно
@@ -235,6 +243,7 @@
 - name: etcd_keepalive_timeout
   type: sec
   default: max(30, etcd_report_interval*2)
+  online: true
   info: |
     Timeout for etcd connection HTTP Keep-Alive. Should be higher than
     etcd_report_interval to guarantee that keepalive actually works.
@@ -244,6 +253,7 @@
 - name: etcd_ws_keepalive_timeout
   type: sec
   default: 30
+  online: true
   info: |
     etcd websocket ping interval required to keep the connection alive and
     detect disconnections quickly.
@@ -252,6 +262,7 @@
 - name: client_dirty_limit
   type: int
   default: 33554432
+  online: true
   info: |
     Without immediate_commit=all this parameter sets the limit of "dirty"
     (not committed by fsync) data allowed by the client before forcing an

docs/config/src/osd.en.md

@@ -1,4 +1,5 @@
 # Runtime OSD Parameters
 
 These parameters only apply to OSDs, are not fixed at the moment of OSD drive
-initialization and can be changed with an OSD restart.
+initialization and can be changed - either with an OSD restart or, for some of
+them, even without restarting by updating configuration in etcd.

docs/config/src/osd.ru.md

@@ -2,4 +2,5 @@
 
 Данные параметры используются только OSD, но, в отличие от дисковых параметров,
 не фиксируются в момент инициализации дисков OSD и могут быть изменены в любой
-момент с перезапуском OSD.
+момент с помощью перезапуска OSD, а некоторые и без перезапуска, с помощью
+изменения конфигурации в etcd.

docs/config/src/osd.yml

@@ -66,6 +66,7 @@
 - name: autosync_interval
   type: sec
   default: 5
+  online: true
   info: |
     Time interval at which automatic fsyncs/flushes are issued by each OSD when
     the immediate_commit mode if disabled. fsyncs are required because without
@@ -83,6 +84,7 @@
 - name: autosync_writes
   type: int
   default: 128
+  online: true
   info: |
     Same as autosync_interval, but sets the maximum number of uncommitted write
     operations before issuing an fsync operation internally.
@@ -93,6 +95,7 @@
 - name: recovery_queue_depth
   type: int
   default: 4
+  online: true
   info: |
     Maximum recovery operations per one primary OSD at any given moment of time.
     Currently it's the only parameter available to tune the speed or recovery
@@ -105,6 +108,7 @@
 - name: recovery_pg_switch
   type: int
   default: 128
+  online: true
   info: |
     Number of recovery operations before switching to recovery of the next PG.
     The idea is to mix all PGs during recovery for more even space and load
@@ -119,6 +123,7 @@
 - name: recovery_sync_batch
   type: int
   default: 16
+  online: true
   info: Maximum number of recovery operations before issuing an additional fsync.
   info_ru: Максимальное число операций восстановления перед дополнительным fsync.
 - name: readonly
@@ -133,6 +138,7 @@
 - name: no_recovery
   type: bool
   default: false
+  online: true
   info: |
     Disable automatic background recovery of objects. Note that it doesn't
     affect implicit recovery of objects happening during writes - a write is
@@ -145,6 +151,7 @@
 - name: no_rebalance
   type: bool
   default: false
+  online: true
   info: |
     Disable background movement of data between different OSDs. Disabling it
     means that PGs in the `has_misplaced` state will be left in it indefinitely.
@@ -155,6 +162,7 @@
 - name: print_stats_interval
   type: sec
   default: 3
+  online: true
   info: |
     Time interval at which OSDs print simple human-readable operation
     statistics on stdout.
@@ -164,6 +172,7 @@
 - name: slow_log_interval
   type: sec
   default: 10
+  online: true
   info: |
     Time interval at which OSDs dump slow or stuck operations on stdout, if
     they're any. Also it's the time after which an operation is considered
@@ -175,6 +184,7 @@
 - name: inode_vanish_time
   type: sec
   default: 60
+  online: true
   info: |
     Number of seconds after which a deleted inode is removed from OSD statistics.
   info_ru: |
@@ -182,6 +192,7 @@
 - name: max_write_iodepth
   type: int
   default: 128
+  online: true
   info: |
     Parallel client write operation limit per one OSD. Operations that exceed
     this limit are pushed to a temporary queue instead of being executed
@@ -193,6 +204,7 @@
 - name: min_flusher_count
   type: int
   default: 1
+  online: true
   info: |
     Flusher is a micro-thread that moves data from the journal to the data
     area of the device. Their number is auto-tuned between minimum and maximum.
@@ -204,6 +216,7 @@
 - name: max_flusher_count
   type: int
   default: 256
+  online: true
   info: |
     Maximum number of journal flushers (see above min_flusher_count).
   info_ru: |
@@ -284,6 +297,7 @@
 - name: throttle_small_writes
   type: bool
   default: false
+  online: true
   info: |
     Enable soft throttling of small journaled writes. Useful for hybrid OSDs
     with fast journal/metadata devices and slow data devices. The idea is that
@@ -312,6 +326,7 @@
 - name: throttle_target_iops
   type: int
   default: 100
+  online: true
   info: |
     Target maximum number of throttled operations per second under the condition
     of full journal. Set it to approximate random write iops of your data devices
@@ -324,6 +339,7 @@
 - name: throttle_target_mbs
   type: int
   default: 100
+  online: true
   info: |
     Target maximum bandwidth in MB/s of throttled operations per second under
     the condition of full journal. Set it to approximate linear write
@@ -336,6 +352,7 @@
 - name: throttle_target_parallelism
   type: int
   default: 1
+  online: true
   info: |
     Target maximum parallelism of throttled operations under the condition of
     full journal. Set it to approximate internal parallelism of your data
@@ -348,6 +365,7 @@
 - name: throttle_threshold_us
   type: us
   default: 50
+  online: true
   info: |
     Minimal computed delay to be applied to throttled operations. Usually
     doesn't need to be changed.