Re: [PATCH v6 COLO 07/15] implement the cmdline for COLO

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 06/16/2015 07:19 PM, Ian Campbell wrote:
> On Mon, 2015-06-08 at 11:45 +0800, Yang Hongyang wrote:
>> From: Wen Congyang <wency@cn.fujitsu.com>
>>
>> Add a new option -c to the command 'xl remus'. If you want
>> to use COLO HA instead of Remus HA, please use -c option.
>>
>> Update man pages to reflect the addition of a new option to
>> 'xl remus' command.
>>
>> Also add a new option -c to the internal command 'xl migrate-receive'.
>
> I asked about whether COLO was an extension or a peer to Remus in an
> earlier patch. the answer may have an impact here too.

We implemented COLO based on Remus, so we assume it is an extension to Remus.

>
>> @@ -498,6 +501,11 @@ Disable network output buffering. Requires enabling unsafe mode.
>>
>>   Disable disk replication. Requires enabling unsafe mode.
>>
>> +=item B<-c>
>> +
>> +Enable COLO HA. It is conflict with B<-i> and B<-b>, and memory
>
> "It conflicts with" or "This conflicts with".
>
>> +checkpoint compression must be disabled.
>> +
>>   =back
>>
>>   =item B<pause> I<domain-id>
>> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
>> index 1145ae4..7df2466 100644
>> --- a/tools/libxl/libxl.c
>> +++ b/tools/libxl/libxl.c
>> @@ -811,6 +811,22 @@ int libxl_domain_remus_start(libxl_ctx *ctx, libxl_domain_remus_info *info,
>>           goto out;
>>       }
>>
>> +    /* The caller must set this defbool */
>> +    if (libxl_defbool_is_default(info->colo)) {
>> +        LOG(ERROR, "colo mode must be enabled/disabled");
>
> As I wondered earlier -- this suggests it should not be a defbool, or
> that the interfaces should split.
>
>> +        rc = ERROR_FAIL;
>> +        goto out;
>> +    }
>> +
>> +    if (libxl_defbool_val(info->colo)) {
>> +        libxl_defbool_setdefault(&info->compression, false);
>
> Assuming this isn't invalidated by the above comments, you should make
> the existing:
>   libxl_defbool_setdefault(&info->compression, true);
> into
>   libxl_defbool_setdefault(&info->compression, libxl_defbool_val(colo));
>
> and then do an error check later.
>
>> +        if (libxl_defbool_val(info->compression)) {
>> +            LOG(ERROR, "cannot use memory checkpoint compression in COLO mode");
>> +            rc = ERROR_FAIL;
>> +            goto out;
>> +        }
>> +    }
>> +
>>       libxl_defbool_setdefault(&info->allow_unsafe, false);
>>       libxl_defbool_setdefault(&info->blackhole, false);
>>       libxl_defbool_setdefault(&info->compression, true);
>> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
>> index adfadd1..4bbadd3 100644
>> --- a/tools/libxl/xl_cmdimpl.c
>> +++ b/tools/libxl/xl_cmdimpl.c
>> @@ -4273,6 +4273,9 @@ static void migrate_receive(int debug, int daemonize, int monitor,
>>       dom_info.send_fd = send_fd;
>>       dom_info.migration_domname_r = &migration_domname;
>>       dom_info.checkpointed_stream = remus;
>> +    if (remus == LIBXL_CHECKPOINTED_STREAM_COLO)
>> +        /* COLO uses stdout to send control message to master */
>> +        dom_info.quiet = 1;
>
> Please set a const char * to either "COLO" or "Remus" here and use it
> everywhere you've currently got an open coded decision on that.
>
>>
>>       rc = create_domain(&dom_info);
>>       if (rc < 0) {
>> @@ -4287,7 +4290,8 @@ static void migrate_receive(int debug, int daemonize, int monitor,
>>           /* If we are here, it means that the sender (primary) has crashed.
>>            * TODO: Split-Brain Check.
>>            */
>> -        fprintf(stderr, "migration target: Remus Failover for domain %u\n",
>> +        fprintf(stderr, "migration target: %s Failover for domain %u\n",
>> +                remus == LIBXL_CHECKPOINTED_STREAM_COLO ? "COLO" : "Remus",
>>                   domid);
>>
>>           /*
>> @@ -4304,15 +4308,21 @@ static void migrate_receive(int debug, int daemonize, int monitor,
>>               rc = libxl_domain_rename(ctx, domid, migration_domname,
>>                                        common_domname);
>>               if (rc)
>> -                fprintf(stderr, "migration target (Remus): "
>> +                fprintf(stderr, "migration target (%s): "
>>                           "Failed to rename domain from %s to %s:%d\n",
>> +                        remus == LIBXL_CHECKPOINTED_STREAM_COLO ? "COLO" : "Remus",
>>                           migration_domname, common_domname, rc);
>>           }
>>
>> +        if (remus == LIBXL_CHECKPOINTED_STREAM_COLO)
>> +            /* The guest is running after failover in COLO mode */
>> +            exit(rc ? -ERROR_FAIL: 0);
>> +
>>           rc = libxl_domain_unpause(ctx, domid);
>>           if (rc)
>> -            fprintf(stderr, "migration target (Remus): "
>> +            fprintf(stderr, "migration target (%s): "
>>                       "Failed to unpause domain %s (id: %u):%d\n",
>> +                    remus == LIBXL_CHECKPOINTED_STREAM_COLO ? "COLO" : "Remus",
>>                       common_domname, domid, rc);
>>
>>           exit(rc ? -ERROR_FAIL: 0);
>> @@ -4458,7 +4468,7 @@ int main_migrate_receive(int argc, char **argv)
>>       int debug = 0, daemonize = 1, monitor = 1, remus = 0;
>>       int opt;
>>
>> -    SWITCH_FOREACH_OPT(opt, "Fedr", NULL, "migrate-receive", 0) {
>> +    SWITCH_FOREACH_OPT(opt, "Fedrc", NULL, "migrate-receive", 0) {
>>       case 'F':
>>           daemonize = 0;
>>           break;
>> @@ -4470,8 +4480,10 @@ int main_migrate_receive(int argc, char **argv)
>>           debug = 1;
>>           break;
>>       case 'r':
>> -        remus = 1;
>> +        remus = LIBXL_CHECKPOINTED_STREAM_REMUS;
>>           break;
>> +    case 'c':
>> +        remus = LIBXL_CHECKPOINTED_STREAM_COLO;
>>       }
>>
>>       if (argc-optind != 0) {
>> @@ -7958,15 +7970,18 @@ int main_remus(int argc, char **argv)
>>       pid_t child = -1;
>>       uint8_t *config_data;
>>       int config_len;
>> +    int interval = 0;
>>
>>       memset(&r_info, 0, sizeof(libxl_domain_remus_info));
>>       /* Defaults */
>>       r_info.interval = 200;
>>       libxl_defbool_setdefault(&r_info.blackhole, false);
>> +    libxl_defbool_setdefault(&r_info.colo, false);
>>
>> -    SWITCH_FOREACH_OPT(opt, "Fbundi:s:N:e", NULL, "remus", 2) {
>> +    SWITCH_FOREACH_OPT(opt, "Fbundi:s:N:ec", NULL, "remus", 2) {
>>       case 'i':
>>           r_info.interval = atoi(optarg);
>> +        interval = 1;
>
> This duplication of r_info.interval and interval seems odd. Perhaps
> interval is really "interval_was_set" but even so I'm not sure this
> would be better achieved with some more refactoring.
>
>>           break;
>>       case 'F':
>>           libxl_defbool_set(&r_info.allow_unsafe, true);
>> @@ -7992,11 +8007,28 @@ int main_remus(int argc, char **argv)
>>       case 'e':
>>           daemonize = 0;
>>           break;
>> +    case 'c':
>> +        libxl_defbool_set(&r_info.colo, true);
>>       }
>>
>>       domid = find_domain(argv[optind]);
>>       host = argv[optind + 1];
>>
>> +    if (libxl_defbool_val(r_info.colo)) {
>> +        if (!interval)
>> +            r_info.interval = 0;
>> +
>> +        if (r_info.interval || libxl_defbool_val(r_info.blackhole)) {
>> +            perror("option -c is conflict with -i or -b");
>
> "...-c conflicts with..."
>
>> +            exit(-1);
>> +        }
>> +
>> +        if (libxl_defbool_is_default(r_info.compression)) {
>> +            perror("option -u must be specified when using COLO");
>
> Then enforce it using setdefault I think instead of making the user jump
> through a pointless hoop.
>
> Ian.
>
> .
>

-- 
Thanks,
Yang.