glusterd, cli: implement gluster system uuid reset command

A commonly faced problem among glusterfs users is: after a fresh
installation of glusterfs in a virtual machine, the VM image is
cloned to make multiple instances of the server. This breaks
glusterd because right after glusterfs installation on the first
boot glusterd would have created the node UUID and this gets
inherited into the clone. The result is wierd behavior at the time
of peer probe where glusterd does not (yet) deal with UUID
collisions in a user friendly way.

To handle it gluster peer reset command is implemented which upon
execution changes the uuid of local glusterd.

Change-Id: If207dd2ad93ab94ef1a3253f409c21c442975f87
BUG: 811493
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-on: http://review.gluster.org/3637
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-handler.c b/xlators/mgmt/glusterd/src/glusterd-handler.c
index 592fbbdb2..cec94f89f 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handler.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handler.c
@@ -921,6 +921,105 @@ out:
 }
 
 int
+glusterd_handle_cli_uuid_reset (rpcsvc_request_t *req)
+{
+        int                     ret     = -1;
+        dict_t                  *dict   = NULL;
+        xlator_t                *this   = NULL;
+        glusterd_conf_t         *priv   = NULL;
+        uuid_t                  uuid    = {0};
+        gf_cli_rsp              rsp     = {0,};
+        gf_cli_req              cli_req = {{0,}};
+        char                    msg_str[2048] = {0,};
+
+        GF_ASSERT (req);
+
+        this = THIS;
+        priv = this->private;
+        GF_ASSERT (priv);
+
+        if (!xdr_to_generic (req->msg[0], &cli_req, (xdrproc_t)xdr_gf_cli_req)) {
+                //failed to decode msg;
+                req->rpc_err = GARBAGE_ARGS;
+                goto out;
+        }
+
+        gf_log ("glusterd", GF_LOG_DEBUG, "Received uuid reset req");
+
+        if (cli_req.dict.dict_len) {
+                /* Unserialize the dictionary */
+                dict  = dict_new ();
+
+                ret = dict_unserialize (cli_req.dict.dict_val,
+                                        cli_req.dict.dict_len,
+                                        &dict);
+                if (ret < 0) {
+                        gf_log ("glusterd", GF_LOG_ERROR,
+                                "failed to "
+                                "unserialize req-buffer to dictionary");
+                        snprintf (msg_str, sizeof (msg_str), "Unable to decode "
+                                  "the buffer");
+                        goto out;
+                } else {
+                        dict->extra_stdfree = cli_req.dict.dict_val;
+                }
+        }
+
+        /* In the above section if dict_unserialize is successful, ret is set
+         * to zero.
+         */
+        ret = -1;
+        // Do not allow peer reset if there are any volumes in the cluster
+        if (!list_empty (&priv->volumes)) {
+                snprintf (msg_str, sizeof (msg_str), "volumes are already "
+                          "present in the cluster. Resetting uuid is not "
+                          "allowed");
+                gf_log (this->name, GF_LOG_WARNING, msg_str);
+                goto out;
+        }
+
+        // Do not allow peer reset if trusted storage pool is already formed
+        if (!list_empty (&priv->peers)) {
+                snprintf (msg_str, sizeof (msg_str),"trusted storage pool "
+                          "has been already formed. Please detach this peer "
+                          "from the pool and reset its uuid.");
+                gf_log (this->name, GF_LOG_WARNING, msg_str);
+                goto out;
+        }
+
+        uuid_copy (uuid, priv->uuid);
+        ret = glusterd_uuid_generate_save ();
+
+        if (!uuid_compare (uuid, MY_UUID)) {
+                snprintf (msg_str, sizeof (msg_str), "old uuid and the new uuid"
+                          " are same. Try gluster peer reset again");
+                gf_log (this->name, GF_LOG_ERROR, msg_str);
+                ret = -1;
+                goto out;
+        }
+
+out:
+        if (ret) {
+                rsp.op_ret = -1;
+                if (msg_str[0] == '\0')
+                        snprintf (msg_str, sizeof (msg_str), "Operation "
+                                  "failed");
+                rsp.op_errstr = msg_str;
+                ret = 0;
+        } else {
+                rsp.op_errstr = "";
+        }
+
+        glusterd_to_cli (req, &rsp, NULL, 0, NULL,
+                         (xdrproc_t)xdr_gf_cli_rsp, dict);
+
+        if (dict)
+                dict_unref (dict);
+
+        return ret;
+}
+
+int
 glusterd_handle_cli_list_volume (rpcsvc_request_t *req)
 {
         int                     ret = -1;
@@ -3035,6 +3134,7 @@ rpcsvc_actor_t gd_svc_cli_actors[] = {
         [GLUSTER_CLI_DEFRAG_VOLUME] = { "CLI_DEFRAG_VOLUME", GLUSTER_CLI_DEFRAG_VOLUME, glusterd_handle_defrag_volume, NULL, 0},
         [GLUSTER_CLI_DEPROBE]       = { "FRIEND_REMOVE", GLUSTER_CLI_DEPROBE, glusterd_handle_cli_deprobe, NULL, 0},
         [GLUSTER_CLI_LIST_FRIENDS]  = { "LIST_FRIENDS", GLUSTER_CLI_LIST_FRIENDS, glusterd_handle_cli_list_friends, NULL, 0},
+        [GLUSTER_CLI_UUID_RESET]    = { "UUID_RESET", GLUSTER_CLI_UUID_RESET, glusterd_handle_cli_uuid_reset, NULL, 0},
         [GLUSTER_CLI_START_VOLUME]  = { "START_VOLUME", GLUSTER_CLI_START_VOLUME, glusterd_handle_cli_start_volume, NULL, 0},
         [GLUSTER_CLI_STOP_VOLUME]   = { "STOP_VOLUME", GLUSTER_CLI_STOP_VOLUME, glusterd_handle_cli_stop_volume, NULL, 0},
         [GLUSTER_CLI_DELETE_VOLUME] = { "DELETE_VOLUME", GLUSTER_CLI_DELETE_VOLUME, glusterd_handle_cli_delete_volume, NULL, 0},