[ovs-dev] [PATCH v5] ovsdb-tool: Convert clustered db to standalone db.

Han Zhou zhouhan at gmail.com
Thu Aug 29 18:32:53 UTC 2019


Thanks for the update. Please see some minor comments below, mostly naming
and documentation.

On Wed, Aug 28, 2019 at 6:32 PM <amginwal at gmail.com> wrote:
>
> From: Aliasgar Ginwala <aginwala at ebay.com>
>
> Add support in ovsdb-tool for migrating clustered dbs to standalone dbs.
> E.g. usage to migrate nb/sb db to standalone db from raft:
> ovsdb-tool cluster-to-standalone ovnnb_db.db ovnnb_db_cluster.db
>
> Signed-off-by: Aliasgar Ginwala <aginwala at ebay.com>
> ---
>  Documentation/ref/ovsdb.7.rst |   3 +
>  ovsdb/ovsdb-tool.1.in         |   8 +++
>  ovsdb/ovsdb-tool.c            | 110 +++++++++++++++++++++++++++++++++-
>  3 files changed, 120 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ref/ovsdb.7.rst b/Documentation/ref/ovsdb.7.rst
> index cd1c63d64..b12d8066c 100644
> --- a/Documentation/ref/ovsdb.7.rst
> +++ b/Documentation/ref/ovsdb.7.rst
> @@ -514,6 +514,9 @@ standalone database from the contents of a running
clustered database.
>  When the cluster is down and cannot be revived, ``ovsdb-client backup``
will
>  not work.
>
> +Use ``ovsdb-tool cluster-to-standalone`` to convert clustered database to
> +standalone database when the cluster is down and cannot be revived.
> +
>  Upgrading or Downgrading a Database
>  -----------------------------------
>
> diff --git a/ovsdb/ovsdb-tool.1.in b/ovsdb/ovsdb-tool.1.in
> index ec85e14c4..8c7962ab3 100644
> --- a/ovsdb/ovsdb-tool.1.in
> +++ b/ovsdb/ovsdb-tool.1.in
> @@ -147,6 +147,14 @@ avoid this possibility, specify
\fB\-\-cid=\fIuuid\fR, where
>  \fIuuid\fR is the cluster ID of the cluster to join, as printed by
>  \fBovsdb\-tool get\-cid\fR.
>  .
> +.SS "Database Migration Commands"
> +This commands will convert cluster database to standalone database.

s/This/These

> +.
> +.IP "\fBcluster-to-standalone \fR[\fIdb\fR [\fIdb\fR]]"

The 2 args are both required (not optional), so please don't add "[ ]".
Same comments to the help messages in ovsdb-tool.c

> +Use this command to convert to standalone database from clustered
database
> +when the cluster is down and cannot be revived. It creates new standalone
> +\fIdb\fR file from the given cluster \fIdb\fR file.
> +.
>  .SS "Version Management Commands"
>  .so ovsdb/ovsdb-schemas.man
>  .PP
> diff --git a/ovsdb/ovsdb-tool.c b/ovsdb/ovsdb-tool.c
> index 438f97590..8039078a3 100644
> --- a/ovsdb/ovsdb-tool.c
> +++ b/ovsdb/ovsdb-tool.c
> @@ -173,6 +173,9 @@ usage(void)
>             "  compare-versions A OP B  compare OVSDB schema version
numbers\n"
>             "  query [DB] TRNS         execute read-only transaction on
DB\n"
>             "  transact [DB] TRNS      execute read/write transaction on
DB\n"
> +           "  cluster-to-standalone [DB [DB]]    Convert clustered DB
to\n"
> +                   "standalone DB when cluster is down and cannot be\n"
> +                    "revived\n"
>             "  [-m]... show-log [DB]   print DB's log entries\n"
>             "The default DB is %s.\n"
>             "The default SCHEMA is %s.\n",
> @@ -942,6 +945,64 @@ print_raft_record(const struct raft_record *r,
>      }
>  }
>
> +static void
> +write_raft_header_to_file(const struct json *data,
> +                          struct ovsdb_log *db_log_data)

Suggest to rename the functions starting with "write_raft_" to something
more clearly tell it is converting from raft to standalone file format,
instead of writing a raft header/record to a clustered DB format. Such as:
raft_header_to_standalone_log().

> +{
> +    if (!data || json_array(data)->n != 2) {
> +       ovs_fatal(0, "***Invalid data***\n");
> +    }
> +
> +    struct json *schema_json = json_array(data)->elems[0];
> +    if (schema_json->type != JSON_NULL) {
> +        struct ovsdb_schema *schema;
> +        check_ovsdb_error(ovsdb_schema_from_json(schema_json, &schema));
> +        ovsdb_schema_destroy(schema);
> +        check_ovsdb_error(ovsdb_log_write_and_free(db_log_data,
schema_json));
> +    }
> +
> +    struct json *data_json = json_array(data)->elems[1];
> +    if (!data_json || data_json->type != JSON_OBJECT) {
> +        ovs_fatal(0, "***invalid data***\n");
> +    }
> +    if (data_json->type != JSON_NULL) {
> +        check_ovsdb_error(ovsdb_log_write_and_free(db_log_data,
data_json));
> +    }
> +}
> +
> +static void
> +write_raft_header(const struct raft_header *h, struct ovsdb_log
*db_log_data)

The function name write_raft_header() and write_raft_header_to_file() seems
doesn't tell the real difference between these two funcitons. Maybe they
can be combined as just one function. Same comment for write_raft_record()
and write_raft_record_to_file().

> +{
> +    if (h->snap_index) {
> +        write_raft_header_to_file(h->snap.data, db_log_data);
> +    }
> +}
> +
> +static void
> +write_raft_record_to_file(const struct json *data,
> +                          struct ovsdb_log *db_log_data)
> +{
> +    if (json_array(data)->n != 2) {
> +        ovs_fatal(0, "***invalid data***\n");
> +    }
> +
> +    struct json *data_json = json_array(data)->elems[1];
> +    if (data_json->type != JSON_NULL) {
> +        check_ovsdb_error(ovsdb_log_write_and_free(db_log_data,
data_json));
> +    }
> +}
> +
> +static void
> +write_raft_record(const struct raft_record *r, struct ovsdb_log
*db_log_data)
> +{
> +    if (r->type == RAFT_REC_ENTRY) {
> +        if (!r->entry.data) {
> +            return;
> +        }
> +        write_raft_record_to_file(r->entry.data, db_log_data);
> +    }
> +}
> +
>  static void
>  do_show_log_cluster(struct ovsdb_log *log)
>  {
> @@ -1511,6 +1572,51 @@ do_compare_versions(struct ovs_cmdl_context *ctx)
>      exit(result ? 0 : 2);
>  }
>
> +static void
> +do_convert_to_standalone(struct ovsdb_log *log, struct ovsdb_log
*db_log_data)
> +{
> +    for (unsigned int i = 0; ; i++) {
> +        struct json *json;
> +        check_ovsdb_error(ovsdb_log_read(log, &json));
> +        if (!json) {
> +            break;
> +        }
> +
> +        if (i == 0) {
> +            struct raft_header h;
> +            check_ovsdb_error(raft_header_from_json(&h, json));
> +            write_raft_header(&h, db_log_data);
> +            raft_header_uninit(&h);
> +        } else {
> +            struct raft_record r;
> +            check_ovsdb_error(raft_record_from_json(&r, json));
> +            write_raft_record(&r, db_log_data);
> +            raft_record_uninit(&r);
> +        }
> +    }
> +}
> +
> +static void
> +do_cluster_standalone(struct ovs_cmdl_context *ctx)
> +{
> +    const char *db_file_name = ctx->argv[1];
> +    const char *cluster_db_file_name = ctx->argv[2];
> +    struct ovsdb_log *log;
> +    struct ovsdb_log *db_log_data;
> +
> +    check_ovsdb_error(ovsdb_log_open(cluster_db_file_name,
> +                                     OVSDB_MAGIC"|"RAFT_MAGIC,
> +                                     OVSDB_LOG_READ_ONLY, -1, &log));
> +    check_ovsdb_error(ovsdb_log_open(db_file_name, OVSDB_MAGIC,
> +                                     OVSDB_LOG_CREATE_EXCL, -1,
&db_log_data));
> +    if (strcmp(ovsdb_log_get_magic(log), RAFT_MAGIC) != 0) {
> +        ovs_fatal(0, "Database is not clustered db.\n");
> +    }
> +    do_convert_to_standalone(log, db_log_data);
> +    check_ovsdb_error(ovsdb_log_commit_block(db_log_data));
> +    ovsdb_log_close(db_log_data);
> +    ovsdb_log_close(log);
> +}
>
>  static void
>  do_help(struct ovs_cmdl_context *ctx OVS_UNUSED)
> @@ -1550,7 +1656,9 @@ static const struct ovs_cmdl_command all_commands[]
= {
>      { "compare-versions", "a op b", 3, 3, do_compare_versions, OVS_RO },
>      { "help", NULL, 0, INT_MAX, do_help, OVS_RO },
>      { "list-commands", NULL, 0, INT_MAX, do_list_commands, OVS_RO },
> -    { NULL, NULL, 0, 0, NULL, OVS_RO },
> +    { "cluster-to-standalone", "[db [clusterdb]]", 2, 2,
> +    do_cluster_standalone, OVS_RW },
> +    { NULL, NULL, 2, 2, NULL, OVS_RO },
>  };
>
>  static const struct ovs_cmdl_command *get_all_commands(void)
> --
> 2.20.1 (Apple Git-117)
>
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