vitess.io/vitess@v0.16.2/changelog/15.0/15.0.0/summary.md (about)

     1  ## Summary
     2  
     3  - **[Known Issues](#known-issues)**
     4  - **[Breaking Changes](#breaking-changes)**
     5    - [Flags](#flags)
     6    - [VTTablet Flag Deletions](#vttablet-flag-deletions)
     7    - [Vindex Interface](#vindex-interface)
     8  - **[Deprecations](#deprecations)**
     9    - [LogStats Table and Keyspace Deprecated](#logstats-table-and-keyspace-deprecated)
    10    - [Orchestrator Integration Deprecation](#orchestrator-integration-deprecation)
    11    - [Connection Pool Prefill](#connection-pool-prefill)
    12    - [InitShardPrimary Deprecation](#initshardprimary-deprecation)
    13  - **[Command-Line Syntax Deprecations](#command-line-syntax-deprecations)**
    14    - [VTTablet Startup Flag Deletions](#vttablet-startup-flag-deletions)
    15    - [VTTablet Startup Flag Deprecations](#vttablet-startup-flag-deprecations)
    16    - [VTBackup Flag Deprecations](#vtbackup-flag-deprecations)
    17  - **[VTGate](#vtgate)**
    18    - [vtgate --mysql-server-pool-conn-read-buffers](#vtgate--mysql-server-pool-conn-read-buffers)
    19  - **[VDiff2](#vdiff2)**
    20    - [Resume Workflow](#resume-workflow)
    21  - **[New command line flags and behavior](#new-command-line)**
    22    - [vtctl GetSchema --table-schema-only](#vtctl-getschema--table-schema-only)
    23    - [Support for Additional Compressors and Decompressors During Backup & Restore](#support-for-additional-compressors-and-decompressors-during-backup-&-restore)
    24    - [Independent OLAP and OLTP Transactional Timeouts](#independant-olap-and-oltp-transactional-timeouts)
    25    - [Support for Specifying Group Information in Calls to VTGate](#support-for-specifying-group-information-in-calls-to-vtgate)
    26  - **[Online DDL Changes](#online-ddl-changes)**
    27    - [Concurrent Vitess Migrations](#concurrent-vitess-migrations)
    28    - [VTCtl Command Changes](#vtctl-command-changes)
    29    - [New Syntax](#new-syntax)
    30  - **[Tablet Throttler](#tablet-throttler)**
    31    - [API Changes](#api-changes)
    32  - **[Mysql Compatibility](#mysql-compatibility)**
    33    - [System Settings](#system-settings)
    34    - [Lookup Vindexes](#lookup-vindexes)
    35  - **[Durability Policy](#durability-policy)**
    36    - [Cross Cell](#cross-cell)
    37  - **[New EXPLAIN Format](#new-explain-format)**
    38    - [FORMAT=vtexplain](#formatvtexplain)
    39  - **[VTOrc](#vtorc)**
    40    - [Old UI Removal and Replacement](#old-ui-removal-and-replacement)
    41    - [Configuration Refactor and New Flags](#configuratoin-refactor-and-new-flags)
    42    - [Example Upgrade](#example-upgrade)
    43    - [Default Configuration Files](#default-configuration-files)
    44  - **[Flags Restructure](#flags-restructure)**
    45    - [Flags Diff](#flags-diff)
    46  
    47  ## <a id="known-issues"/>Known Issues
    48  
    49  - [Corrupted results for non-full-group-by queries with JOINs](https://github.com/vitessio/vitess/issues/11625). This can be resolved by using full-group-by queries.
    50  
    51  ## Major Changes
    52  
    53  ### <a id="breaking-changes"/>Breaking Changes
    54  
    55  #### <a id="flags"/>Flags
    56  
    57  - The deprecated `--cpu_profile` flag has been removed. Please use the `--pprof` flag instead.
    58  - The deprecated `--mem-profile-rate` flag has been removed. Please use `--pprof=mem` instead.
    59  - The deprecated `--mutex-profile-fraction` flag has been removed. Please use `--pprof=mutex` instead.
    60  - The deprecated vtgate/vtexplain/vtcombo flag `--planner_version` has been removed. Please use `--planner-version` instead.
    61  - The deprecated flag `--master_connect_retry` has been removed. Please use `--replication_connect_retry` instead.
    62  - `vtctl` commands that take shard names and ranges as positional arguments (e.g. `vtctl Reshard ks.workflow -80 -40,40-80`) need to have their positional arguments separated from their flag arguments by a double-dash separator to avoid the new parsing library from mistaking them as flags (e.g. `vtctl Reshard ks.workflow -- -80 -40,40-80`).
    63  - The `--cell` flag in the `vtgate` binary no longer has a default value. It is a required argument that has to be specified for the binary to run. Please explicitly specify the flag, if dependent on the flag's default value.
    64  - The `--db-config-*-*` VTTablet flags were deprecated in `v3.0.0`. They have now been deleted as part of this release. You must use `--db_dba_*` now.
    65  
    66  #### <a id="vttablet-flag-deletions"/>vttablet Flag Deletions
    67  The following VTTablet flags were deprecated in 7.0. They have now been deleted
    68  - `--queryserver-config-message-conn-pool-size`
    69  - `--queryserver-config-message-conn-pool-prefill-parallelism`
    70  - `--client-found-rows-pool-size` A different existing flag `--queryserver-config-transaction-cap` will be used instead
    71  - `--transaction_shutdown_grace_period` Use `--shutdown_grace_period` instead
    72  - `--queryserver-config-max-dml-rows`
    73  - `--queryserver-config-allowunsafe-dmls`
    74  - `--pool-name-prefix`
    75  - `--enable-autocommit` Autocommit is always allowed
    76  
    77  #### <a id="vindex-interface"/>Vindex Interface
    78  
    79  All the vindex interface methods are changed by adding `context.Context` as an input parameter.
    80  
    81  E.g:
    82  ```go
    83  Map(vcursor VCursor, .... ) .... 
    84  	To
    85  Map(ctx context.Context, vcursor VCursor, .... ) ....
    86  ```
    87  
    88  This only affects users who have added their own custom vindex implementation. 
    89  They are required to change their implementation with these new interface method expectations.
    90  
    91  ### <a id="deprecations"/>Deprecations
    92  
    93  #### <a id="logstats-table-and-keyspace-deprecated"/>LogStats Table and Keyspace deprecated
    94  
    95  Information about which tables are used was being reported through the `Keyspace` and `Table` fields on LogStats.
    96  For multi-table queries, this output can be confusing, so we have added `TablesUsed`, that is a string array, listing all tables and which keyspace they are on.
    97  `Keyspace` and `Table` fields are deprecated and will be removed in the v16 release of Vitess.
    98  
    99  #### <a id="orchestrator-integration-deprecation"/>Orchestrator Integration Deprecation
   100  
   101  Orchestrator integration in `vttablet` has been deprecated. It will continue to work in this release but is liable to be removed in future releases.
   102  Consider using VTOrc instead of Orchestrator as VTOrc goes GA in this release.
   103  
   104  #### <a id="connection-pool-prefill"/>Connection Pool Prefill
   105  
   106  The connection pool with prefilled connections have been removed. The pool now does lazy connection creation.
   107  
   108  #### <a id="initshardprimary-deprecation"/>InitShardPrimary Deprecation
   109  
   110  The vtcltd command InitShardPrimary has been deprecated. Please use PlannedReparentShard instead.
   111  
   112  ### <a id="command-line-syntax-deprecations"/>Command-line syntax deprecations
   113  
   114  #### <a id="vttablet-startup-flag-deletions"/>vttablet startup flag deletions
   115  The following VTTablet flags were deprecated in 7.0. They have now been deleted
   116  - --queryserver-config-message-conn-pool-size
   117  - --queryserver-config-message-conn-pool-prefill-parallelism
   118  - --client-found-rows-pool-size --queryserver-config-transaction-cap will be used instead
   119  - --transaction_shutdown_grace_period Use --shutdown_grace_period instead
   120  - --queryserver-config-max-dml-rows
   121  - --queryserver-config-allowunsafe-dmls
   122  - --pool-name-prefix
   123  - --enable-autocommit Autocommit is always allowed
   124  
   125  #### <a id="vttablet-startup-flag-deprecations"/>vttablet startup flag deprecations
   126  - `--enable-query-plan-field-caching` has been deprecated. It will be removed in v16.
   127  - `--enable_semi_sync` has been deprecated. It will be removed in v16. Instead, set the correct durability policy using `SetKeyspaceDurabilityPolicy`
   128  - `--queryserver-config-pool-prefill-parallelism`, `--queryserver-config-stream-pool-prefill-parallelism` and `--queryserver-config-transaction-prefill-parallelism` have all been deprecated. They will be removed in v16.
   129  - `--backup_storage_hook` has been deprecated, consider using one of the builtin compression algorithms or `--external-compressor` and `--external-decompressor` instead.
   130  
   131  #### <a id="vtbackup-flag-deprecations"/>vtbackup flag deprecations
   132  - `--backup_storage_hook` has been deprecated, consider using one of the builtin compression algorithms or `--external-compressor` and `--external-decompressor` instead.
   133  
   134  ### <a id="vtgate"/>VTGate
   135  
   136  #### <a id="vtgate--mysql-server-pool-conn-read-buffers"/>vtgate --mysql-server-pool-conn-read-buffers
   137  
   138  `--mysql-server-pool-conn-read-buffers` enables pooling of buffers used to read from incoming
   139  connections, similar to the way pooling happens for write buffers. Defaults to off.
   140  
   141  ### <a id="vdiff2"/>VDiff v2
   142  
   143  #### <a id="resume-workflow"/>Resume Workflow
   144  
   145  We introduced the ability to resume a VDiff2 workflow:
   146  ```
   147  $ vtctlclient --server=localhost:15999 VDiff --v2 customer.commerce2customer resume 4c664dc2-eba9-11ec-9ef7-920702940ee0
   148  VDiff 4c664dc2-eba9-11ec-9ef7-920702940ee0 resumed on target shards, use show to view progress
   149  
   150  $ vtctlclient --server=localhost:15999 VDiff --v2 customer.commerce2customer show last
   151  
   152  VDiff Summary for customer.commerce2customer (4c664dc2-eba9-11ec-9ef7-920702940ee0)
   153  State:        completed
   154  RowsCompared: 196
   155  HasMismatch:  false
   156  StartedAt:    2022-06-26 22:44:29
   157  CompletedAt:  2022-06-26 22:44:31
   158  
   159  Use "--format=json" for more detailed output.
   160  
   161  $ vtctlclient --server=localhost:15999 VDiff --v2 --format=json customer.commerce2customer show last
   162  {
   163  	"Workflow": "commerce2customer",
   164  	"Keyspace": "customer",
   165  	"State": "completed",
   166  	"UUID": "4c664dc2-eba9-11ec-9ef7-920702940ee0",
   167  	"RowsCompared": 196,
   168  	"HasMismatch": false,
   169  	"Shards": "0",
   170  	"StartedAt": "2022-06-26 22:44:29",
   171  	"CompletedAt": "2022-06-26 22:44:31"
   172  }
   173  ```
   174  
   175  We leverage this resume capability to automatically restart a VDiff2 workflow that encountered a retryable error.
   176  
   177  We also made a number of other enhancements like progress reporting and features needed to make it a full replacement for VDiff v1. You can see more details in the tracking ticket for the VDiff2 feature complete target: https://github.com/vitessio/vitess/issues/10494
   178  
   179  Now that VDiff v2 is feature complete in 15.0, we hope to make it GA in 16.0.
   180  
   181  Please see the VDiff2 [documentation](https://vitess.io/docs/15.0/reference/vreplication/vdiff2/) for additional information.
   182  
   183  ### <a id="new-command-line"/>New command line flags and behavior
   184  
   185  #### <a id="vtctl-getschema--table-schema-only"/>vtctl GetSchema --table-schema-only
   186  
   187  The new flag `--table-schema-only` skips column introspection. `GetSchema` only returns general schema analysis, and specifically it includes the `CREATE TABLE|VIEW` statement in the `schema` field.
   188  
   189  #### <a id="support-for-additional-compressors-and-decompressors-during-backup-&-restore"/>Support for additional compressors and decompressors during backup & restore
   190  Backup/Restore now allow you many more options for compression and decompression instead of relying on the default compressor(`pargzip`).
   191  There are some built-in compressors which you can use out-of-the-box. Users will need to evaluate which option works best for their
   192  use-case. Here are the flags that control this feature
   193  
   194  - `--compression-engine-name`
   195  - `--external-compressor`
   196  - `--external-decompressor`
   197  - `--external-compressor-extension`
   198  - `--compression-level`
   199  
   200  `--compression-engine-name` specifies the engine used for compression. It can have one of the following values
   201  
   202  - pargzip (Default)
   203  - pgzip
   204  - lz4
   205  - zstd
   206  - external
   207  
   208  If you want to use any of the built-in compressors, simply set one of the above values other than `external` for `--compression-engine-name`. The value
   209  specified in `--compression-engine-name` is saved in the backup MANIFEST, which is later read by the restore process to decide which
   210  engine to use for decompression. Default value for engine is 'pargzip'.
   211  
   212  If you would like to use a custom command or external tool for compression/decompression then you need to provide the full command with
   213  arguments to the `--external-compressor` and `--external-decompressor` flags. `--external-compressor-extension` flag also needs to be provided
   214  so that compressed files are created with the correct extension. If the external command is not using any of the built-in compression engines
   215  (i.e. pgzip, pargzip, lz4 or zstd) then you need to set `--compression-engine-name` to value 'external'.
   216  
   217  Please note that if you want to keep the current behavior then you don't need to provide any of these flags.
   218  You can read more about backup & restore [here] (https://vitess.io/docs/15.0/user-guides/operating-vitess/backup-and-restore/).
   219  
   220  If you decided to switch from an external compressor to one of the built-in supported compressors (i.e. pgzip, pargzip, lz4 or zstd) at any point
   221  in the future, you will need to do it in two steps.
   222  
   223  - step #1, set `--external-compressor` and `--external-compressor-extension` flag values to empty and change `--compression-engine-name` to desired value.
   224  - Step #2, after at least one cycle of backup with new configuration, you can set `--external-decompressor` flag value to empty.
   225  
   226  The reason you cannot change all the values together is because the restore process will then have no way to find out which external decompressor
   227  should be used to process the previous backup. Please make sure you have thought out all possible scenarios for restore before transitioning from one
   228  compression engine to another.
   229  
   230  #### <a id="independant-olap-and-oltp-transactional-timeouts"/>Independent OLAP and OLTP transactional timeouts
   231  
   232  `--queryserver-config-olap-transaction-timeout` specifies the timeout applied
   233  to a transaction created within an OLAP workload. The default value is `30`
   234  seconds, but this can be raised, lowered, or set to zero to disable the timeout
   235  altogether.
   236  
   237  Until now, while OLAP queries would bypass the query timeout, transactions
   238  created within an OLAP session would be rolled back
   239  `--queryserver-config-transaction-timeout` seconds after the transaction was
   240  started.
   241  
   242  As of now, OLTP and OLAP transaction timeouts can be configured independently of each
   243  other.
   244  
   245  The main use case is to run queries spanning a long period of time which
   246  require transactional guarantees such as consistency or atomicity.
   247  
   248  #### <a id="support-for-specifying-group-information-in-calls-to-vtgate"/>Support for specifying group information in calls to VTGate
   249  
   250  `--grpc-use-effective-groups` allows non-SSL callers to specify groups information for a caller.
   251  Until now, you could only specify the caller-id for the security context used to authorize queries.
   252  As of now, you can specify the principal of the caller, and any groups they belong to.
   253  
   254  ### <a id="online-ddl-changes"/>Online DDL changes
   255  
   256  #### <a id="concurrent-vitess-migrations"/>Concurrent vitess migrations
   257  
   258  All Online DDL migrations using the `vitess` strategy are now eligible to run concurrently, given `--allow-concurrent` DDL strategy flag. Until now, only `CREATE`, `DROP` and `REVERT` migrations were eligible, and now `ALTER` migrations are supported, as well. The terms for `ALTER` migrations concurrency:
   259  
   260  - DDL strategy must be `vitess --allow-concurent ...`
   261  - No two migrations can run concurrently on the same table
   262  - No two `ALTER`s will copy table data concurrently
   263  - A concurrent `ALTER` migration will not start if another `ALTER` is running and is not `ready_to_complete`
   264  
   265  The main use case is to run multiple concurrent migrations, all with `--postpone-completion`. All table-copy operations will run sequentially, but no migration will actually cut-over, and eventually all migrations will be `ready_to_complete`, continuously tailing the binary logs and keeping up-to-date. A quick and iterative `ALTER VITESS_MIGRATION '...' COMPLETE` sequence of commands will cut-over all migrations _closely together_ (though not atomically together).
   266  
   267  #### <a id="vtctl-command-changes"/>vtctl command changes. 
   268  All `online DDL show` commands can now be run with a few additional parameters
   269  - `--order` , order migrations in the output by either ascending or descending order of their `id` fields.
   270  - `--skip`  , skip specified number of migrations in the output.
   271  - `--limit` , limit results to a specified number of migrations in the output.
   272  
   273  #### <a id="new-syntax"/>New syntax
   274  
   275  The following is now supported:
   276  
   277  ```sql
   278  ALTER VITESS_MIGRATION COMPLETE ALL
   279  ```
   280  
   281  This works on all pending migrations (`queued`, `ready`, `running`) and internally issues a `ALTER VITESS_MIGRATION '<uuid>' COMPLETE` for each one. The command is useful for completing multiple concurrent migrations (see above) that are open-ended (`--postpone-completion`).
   282  
   283  ### <a id="tablet-throttler"/>Tablet Throttler
   284  
   285  #### <a id="api-changes"/>API changes
   286  
   287  API endpoint `/debug/vars` now exposes throttler metrics, such as number of hits and errors per app per check type. Example:
   288  
   289  ```shell
   290  $ curl -s http://127.0.0.1:15100/debug/vars | jq . | grep Throttler
   291    "ThrottlerAggregatedMysqlSelf": 0.191718,
   292    "ThrottlerAggregatedMysqlShard": 0.960054,
   293    "ThrottlerCheckAnyError": 27,
   294    "ThrottlerCheckAnyMysqlSelfError": 13,
   295    "ThrottlerCheckAnyMysqlSelfTotal": 38,
   296    "ThrottlerCheckAnyMysqlShardError": 14,
   297    "ThrottlerCheckAnyMysqlShardTotal": 42,
   298    "ThrottlerCheckAnyTotal": 80,
   299    "ThrottlerCheckMysqlSelfSecondsSinceHealthy": 0,
   300    "ThrottlerCheckMysqlShardSecondsSinceHealthy": 0,
   301    "ThrottlerProbesLatency": 355523,
   302    "ThrottlerProbesTotal": 74,
   303  ```
   304  
   305  ### <a id="mysql-compatibility"/>Mysql Compatibility
   306  
   307  #### <a id="system-settings"/>System Settings
   308  Vitess has had support for system settings from release 7.0 onwards, but this support came with some caveats.
   309  As soon as a client session changes a default system setting, a mysql connection gets reserved for it.
   310  This can sometimes lead to clients running out of mysql connections. 
   311  Users were instructed to minimize the use of this feature and to try to set the desired system settings as defaults in the mysql config.
   312  
   313  With this release, Vitess can handle system settings changes in a much better way and clients can use them more freely.
   314  Vitess now has the ability to pool changed settings without reserving connections for any particular session. 
   315  
   316  This feature can be enabled by setting `queryserver-enable-settings-pool` flag on the vttablet. It is disabled by default.
   317  In future releases, we will make this flag enabled by default.
   318  
   319  #### <a id="lookup-vindexes"/>Lookup Vindexes
   320  
   321  Lookup vindexes now support a new parameter `multi_shard_autocommit`. If this is set to `true`, lookup vindex dml queries will be sent as autocommit to all shards instead of being wrapped in a transaction.
   322  This is different from the existing `autocommit` parameter where the query is sent in its own transaction separate from the ongoing transaction if any i.e. begin -> lookup query execs -> commit/rollback
   323  
   324  ### <a id="durability-policy"/>Durability Policy
   325  
   326  #### <a id="cross-cell"/>Cross Cell
   327  
   328  A new durability policy `cross_cell` is now supported. `cross_cell` durability policy only allows replica tablets from a different cell than the current primary to
   329  send semi-sync ACKs. This ensures that any committed write exists in at least 2 tablets belonging to different cells.
   330  
   331  ### <a id="new-explain-format"/>New EXPLAIN format
   332  
   333  #### <a id="format=vtexplain"/>FORMAT=vtexplain
   334  
   335  With this new `explain` format, you can get an output that is very similar to the command line `vtexplain` app, but from a running `vtgate`, through a MySQL query.
   336  
   337  ### <a id="vtorc"/>VTOrc
   338  
   339  #### <a id="old-ui-removal-and-replacement"/>Old UI Removal and Replacement
   340  
   341  The old UI that VTOrc inherited from `Orchestrator` has been removed. A replacement UI, more consistent with the other Vitess binaries has been created.
   342  In order to use the new UI, `--port` flag has to be provided. 
   343  
   344  Along with the UI, the old APIs have also been deprecated. However, some of them have been ported over to the new UI - 
   345  
   346  | Old API                          | New API                          | Additional notes                                                      |
   347  |----------------------------------|----------------------------------|-----------------------------------------------------------------------|
   348  | `/api/problems`                  | `/api/problems`                  | The new API also supports filtering using the keyspace and shard name |
   349  | `/api/disable-global-recoveries` | `/api/disable-global-recoveries` | Functionally remains the same                                         |
   350  | `/api/enable-global-recoveries`  | `/api/enable-global-recoveries`  | Functionally remains the same                                         |
   351  | `/api/health`                    | `/debug/health`                  | Functionally remains the same                                         |
   352  | `/api/replication-analysis`      | `/api/replication-analysis`      | Functionally remains the same. Output is now JSON format.             |
   353  
   354  Apart from these APIs, we also now have `/debug/status`, `/debug/vars` and `/debug/liveness` available in the new UI.
   355  
   356  #### <a id="configuratoin-refactor-and-new-flags"/>Configuration Refactor and New Flags 
   357  
   358  Since VTOrc was forked from `Orchestrator`, it inherited a lot of configurations that don't make sense for the Vitess use-case.
   359  All of such configurations have been removed.
   360  
   361  VTOrc ignores the configurations that it doesn't understand. So old configurations can be kept around on upgrading and won't cause any issues.
   362  They will just be ignored.
   363  
   364  For all the configurations that are kept, flags have been added for them and the flags are the desired way to pass these configurations going forward.
   365  The config file will be deprecated and removed in upcoming releases. The following is a list of all the configurations that are kept and the associated flags added.
   366  
   367  |          Configurations Kept          |           Flags Introduced            |
   368  |:-------------------------------------:|:-------------------------------------:|
   369  |            SQLite3DataFile            |         `--sqlite-data-file`          |
   370  |          InstancePollSeconds          |        `--instance-poll-time`         |
   371  |    SnapshotTopologiesIntervalHours    |    `--snapshot-topology-interval`     |
   372  |    ReasonableReplicationLagSeconds    |    `--reasonable-replication-lag`     |
   373  |             AuditLogFile              |        `--audit-file-location`        |
   374  |             AuditToSyslog             |         `--audit-to-backend`          |
   375  |           AuditToBackendDB            |          `--audit-to-syslog`          |
   376  |            AuditPurgeDays             |       `--audit-purge-duration`        |
   377  |      RecoveryPeriodBlockSeconds       |  `--recovery-period-block-duration`   |
   378  | PreventCrossDataCenterPrimaryFailover |    `--prevent-cross-cell-failover`    |
   379  |        LockShardTimeoutSeconds        |        `--lock-shard-timeout`         |
   380  |      WaitReplicasTimeoutSeconds       |       `--wait-replicas-timeout`       |
   381  |     TopoInformationRefreshSeconds     | `--topo-information-refresh-duration` |
   382  |          RecoveryPollSeconds          |      `--recovery-poll-duration`       |
   383  
   384  Apart from configurations, some flags from VTOrc have also been removed -
   385  - `sibling`
   386  - `destination`
   387  - `discovery`
   388  - `skip-unresolve`
   389  - `skip-unresolve-check`
   390  - `noop`
   391  - `binlog`
   392  - `statement`
   393  - `grab-election`
   394  - `promotion-rule`
   395  - `skip-continuous-registration`
   396  - `enable-database-update`
   397  - `ignore-raft-setup`
   398  - `tag`
   399  
   400  The ideal way to ensure backward compatibility is to remove the flags listed above while on the previous release. Then upgrade VTOrc.
   401  After upgrading, remove the config file and instead pass the flags that are introduced.
   402  
   403  #### <a id="example-upgrade"/>Example Upgrade
   404  
   405  If you are running VTOrc with the flags `--ignore-raft-setup --clusters_to_watch="ks/0" --config="path/to/config"` and the following configuration
   406  ```json
   407  {
   408    "Debug": true,
   409    "ListenAddress": ":6922",
   410    "MySQLTopologyUser": "orc_client_user",
   411    "MySQLTopologyPassword": "orc_client_user_password",
   412    "MySQLReplicaUser": "vt_repl",
   413    "MySQLReplicaPassword": "",
   414    "RecoveryPeriodBlockSeconds": 1,
   415    "InstancePollSeconds": 1,
   416    "PreventCrossDataCenterPrimaryFailover": true
   417  }
   418  ```
   419  First drop the flag `--ignore-raft-setup` while on the previous release. So, you'll be running VTOrc with `--clusters_to_watch="ks/0" --config="path/to/config"` and the same configuration listed above.
   420  
   421  Now you can upgrade your VTOrc version continuing to use the same flags and configurations, and it will continue to work just the same. If you wish to use the new UI, then you can add the `--port` flag as well.
   422  
   423  After upgrading, you can drop the configuration entirely and use the new flags like `--clusters_to_watch="ks/0" --recovery-period-block-duration=1s --instance-poll-time=1s --prevent-cross-cell-failover`
   424  
   425  #### <a id="default-configuration-files"/>Default Configuration Files
   426  
   427  The default files that VTOrc searches for configurations in have also changed from `"/etc/orchestrator.conf.json", "conf/orchestrator.conf.json", "orchestrator.conf.json"` to
   428  `"/etc/vtorc.conf.json", "conf/vtorc.conf.json", "vtorc.conf.json"`.
   429  
   430  ### <a id="flags-restructure"/>Flags Restructure
   431  
   432  #### <a id="flags-diff"/>Flags Diff
   433  
   434  In addition to these major streams of work in release-15.0, we have made tremendous progress on [VEP-4, aka The Flag Situation](https://github.com/vitessio/enhancements/blob/main/veps/vep-4.md), reorganizing our code so that Vitess binaries and their flags are
   435  clearly aligned in help text. An immediate win for usability, this positions us well to move on to a [viper](https://github.com/spf13/viper) implementation which will facilitate additional improvements including standardization of flag syntax and runtime configuration reloads.
   436  We are also aligning with industry standards regarding the use of flags, ensuring a seamless experience for users migrating from or integrating with other platforms.
   437  Below are the changes for each binary.
   438  - [mysqlctl](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/mysqlctl.diff)
   439  - [mysqlctld](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/mysqlctld.diff)
   440  - [vtaclcheck](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtaclcheck.diff)
   441  - [vtadmin](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtadmin.diff)
   442  - [vtctlclient](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtctlclient.diff)
   443  - [vtctld](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtctld.diff)
   444  - [vtctldclient](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtctldclient.diff)
   445  - [vtexplain](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtexplain.diff)
   446  - [vtgate](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtgate.diff)
   447  - [vtgtr](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtgtr.diff)
   448  - [vtorc](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vtorc.diff)
   449  - [vttablet](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vttablet.diff)
   450  - [vttestserver](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vttestserver.diff)
   451  - [vttlstest](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/vttlstest.diff)
   452  - [zk](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/zk.diff)
   453  - [zkctl](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/zkctl.diff)
   454  - [zkctld](https://github.com/vitessio/vitess/blob/release-15.0/doc/flags/14.0-to-15.0-transition/zkctld.diff)