MDEV-18863: Galera SST scripts can't read [mysqldN] option groups

Some users and some scripts (for example, mysqld_multi.sh) use special
option groups with names like [mysqld1], [mysqld2], ..., [mysqldN].

But SST scripts can't currently fully support these option groups.
The only option group-related value it gets from the server is
--defaults-group-suffix, if that option was set for mysqld when
the server was started.

However, the SST scripts does not get told by the server to read
these option groups, so this means that the SST script will fail
to read options like innodb-data-home-dir when it is in a option
group like [mysqld1]...[mysqldN].

Moreover, SST scripts ignore many parameters that can be passed
to them explicitly and cannot transfer them further, for example,
to the input of mariabackup utility. Ideally, we want to transfer
all the parameters of the original mysqld call to utilities such
as mariabackup, however the SST script does not receive these
parameters from the server and therefore cannot transfer them to
mariabackup.

To correct these shortcomings, we need to transfer to the scripts
all of the parameters of the original mysqld call, and in the SST
scripts themselves provide for the transfer all of these parameters
to utilities such as mariabackup. To prevent these parameters from
mixing with the script's own parameters, they should be transferred
to SST script after the special option "--mysqld-args", followed by
the string argument with the original parameters, as it received by
the mysqld call at the time of launch (further all these parameters
will be passed to mariabackup, for example).

In addition, the SST scripts themselves must be refined so that
they can read the parameters from the user-selected group, not just
from the global mysqld configuration group. And also so that they
can receive the parameters (which important for their work) as
command-line arguments.

1 files changed, 32 insertions, 6 deletions

diff --git a/scripts/wsrep_sst_mariabackup.sh b/scripts/wsrep_sst_mariabackup.sh
index 5d07380abf5..abcfa0aea35 100644
--- a/scripts/wsrep_sst_mariabackup.sh
+++ b/scripts/wsrep_sst_mariabackup.sh
@@ -698,8 +698,7 @@ if [[ ${FORCE_FTWRL:-0} -eq 1 ]];then
     iopts+=" --no-backup-locks "
 fi
 
-
-INNOEXTRA=""
+INNOEXTRA=$WSREP_SST_OPT_MYSQLD
 
 INNODB_DATA_HOME_DIR=${INNODB_DATA_HOME_DIR:-""}
 # Try to set INNODB_DATA_HOME_DIR from the command line:
@@ -708,6 +707,9 @@ if [ ! -z "$INNODB_DATA_HOME_DIR_ARG" ]; then
 fi
 # if INNODB_DATA_HOME_DIR env. variable is not set, try to get it from my.cnf
 if [ -z "$INNODB_DATA_HOME_DIR" ]; then
+    INNODB_DATA_HOME_DIR=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-data-home-dir '')
+fi
+if [ -z "$INNODB_DATA_HOME_DIR" ]; then
     INNODB_DATA_HOME_DIR=$(parse_cnf --mysqld innodb-data-home-dir '')
 fi
 if [ ! -z "$INNODB_DATA_HOME_DIR" ]; then
@@ -827,7 +829,9 @@ then
             exit 93
         fi
 
-        if [[ -z $(parse_cnf --mysqld tmpdir "") && -z $(parse_cnf xtrabackup tmpdir "") ]];then 
+        if [[ -z $(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE tmpdir "") && \
+              -z $(parse_cnf --mysqld tmpdir "") && \
+              -z $(parse_cnf xtrabackup tmpdir "") ]]; then
             xtmpdir=$(mktemp -d)
             tmpopts=" --tmpdir=$xtmpdir "
             wsrep_log_info "Using $xtmpdir as xtrabackup temporary directory"
@@ -950,8 +954,24 @@ then
     [[ -n $SST_PROGRESS_FILE ]] && touch $SST_PROGRESS_FILE
 
     ib_home_dir=$INNODB_DATA_HOME_DIR
-    ib_log_dir=$(parse_cnf --mysqld innodb-log-group-home-dir "")
-    ib_undo_dir=$(parse_cnf --mysqld innodb-undo-directory "")
+
+    # Try to set ib_log_dir from the command line:
+    ib_log_dir=$INNODB_LOG_GROUP_HOME_ARG
+    if [ -z "$ib_log_dir" ]; then
+        ib_log_dir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-log-group-home-dir "")
+    fi
+    if [ -z "$ib_log_dir" ]; then
+        ib_log_dir=$(parse_cnf --mysqld innodb-log-group-home-dir "")
+    fi
+
+    # Try to set ib_undo_dir from the command line:
+    ib_undo_dir=$INNODB_UNDO_DIR_ARG
+    if [ -z "$ib_undo_dir" ]; then
+        ib_undo_dir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE innodb-undo-directory "")
+    fi
+    if [ -z "$ib_undo_dir" ]; then
+        ib_undo_dir=$(parse_cnf --mysqld innodb-undo-directory "")
+    fi
 
     stagemsg="Joiner-Recv"
 
@@ -1028,7 +1048,13 @@ then
             find $ib_home_dir $ib_log_dir $ib_undo_dir $DATA -mindepth 1 -prune -regex $cpat -o -exec rm -rfv {} 1>&2 \+
 	fi
 
-        tempdir=$(parse_cnf --mysqld log-bin "")
+        tempdir=$LOG_BIN_ARG
+        if [ -z "$tempdir" ]; then
+           tempdir=$(parse_cnf mysqld$WSREP_SST_OPT_SUFFIX_VALUE log-bin "")
+        fi
+        if [ -z "$tempdir" ]; then
+            tempdir=$(parse_cnf --mysqld log-bin "")
+        fi
         if [[ -n ${tempdir:-} ]];then
             binlog_dir=$(dirname $tempdir)
             binlog_file=$(basename $tempdir)