Synced xtrabackup SST scripts from PXC source tree as of PXC 5.6.27-25.13
- PXC#480: xtrabackup-v2 SST fails with multiple log_bin directives in my.cn
- PXC#460: wsrep_sst_auth don't work in Percona-XtraDB-Cluster-56-5.6.25-25.
- PXC-416: Fix SST related issues.
- PXC-389: Merge remote-tracking branch 'wsrep/5.6' into 5.6-wsrep-pxc389
- Bug #1431101: SST does not clobber backup-my.cnf
In rsync based SST method, during third phase of data transfer,
'lost+found' should be filtered out while recursively transferring
files from various directories under data directory.
During wsrep position recovery, galera_recovery.sh script
redirected mysqld's error log to a temporary file in order
to find the start position. This, however, will not work
if --log-error is configured for the server.
Fixed by using --log-error in command line instead of
redirection.
[Patch contributed by Philippe MARASSE]
Using IP address in donor's socat with TLS/SSL and certificate
which doesn't contain IP address in CN or SubjectAltName causes
transfer to fail with message:
socat[5799] E certificate is valid but its commonName does not
match hostname.
This patch tries to reverse resolve IP address to hostname and
use it for transfer. If reverse resolution fails, IP address is
still used as fall-back, so proper A/AAAA and PTR records are
important, but not mandatory.
Certain certificates cannot contain IP addresses, e.g. FreeIPA's
Dogtag doesn't allow it, so in my case I would need to use self-
signed certificates instead, use verify=0 with socat or don't use
TLS/SSL at all. Issue is mentioned in MDEV-9403.
Galera recovery process works in two phases. In the first
phase, mysqld is started as non-daemon with --wsrep-recover
to recover and fetch the last logged global transaction ID.
This ID is then used in second phase as the start position
(--wsrep-start-position=XX) to start mysqld as daemon.
As this process was implemented in mysqld_safe script, the
recovery did not work when server was started using systemd.
Fixed by introducing a shell script (wsrep_recovery.sh) that
mimics the first phase of the recovery process.
Added mysql_to_mariadb.sql script, to change mysql.user tables from
MySQL 5.7 to MariaDB.
After this script is run, one can get the other tables fixed by running
mysql_upgrade
[Fix taken from https://github.com/percona/percona-xtradb-
cluster/commit/b3ee75949ed82b88f355ca2e26431350cc1c89ac]
During SST, the receiver node creates .sst directory under
datadir to process/prepare the received data and removes it
at the end of the process. In case of error, this directory,
however, was not removed, which later caused subsequent SSTs
to fail. Fixed by removing this directory at the beginning
of SST if it existed.
IS NOT FOUND
DESCRIPTION
===========
If script mysqld_multi and utility my_print_defaults are in
the same folder (not included in $PATH) and the former is
made to run, it complaints that the mysqld binary is absent
eventhough the binary exists.
ANALYSIS
========
We've a subroutine my_which() mimicking the behaviour of
POSIX "which" command. Its current behaviour is to check
for a given argument as follows:
- Step 1: Assume the argument to be a command having full
fledged absolute path. If it exists "as-is", return the
argument (which will be pathname), else proceed to Step 2.
- Step 2: Assume the argument to be a plain command with no
aboslute path. Try locating it in all of the paths
(mentioned in $PATH) one by one. If found return the
pathname. If found nowhere, return NULL.
Currently when my_which(my_print_defaults) is called, it
returns from Step 1 (since utlity exists in current
folder) and doesn't proceed to Step 2. This is wrong since
the returned value is same as the argument i.e.
'my_print_default' which defies the purpose of this
subroutine whose job is to return a pathname either in Step
1 or Step 2.
Later when the utility is executed in subroutine
defaults_for_group(), it evaluates to NULL and returns the
same. This is because the plain command 'my_print_defaults
{options} ...' would execute properly only if
my_print_defaults exists in one of the paths (in $PATH). In
such a case, in the course of the flow it looks onto the
variable $mysqld_found which comes out to be NULL and
hence ethe error.
In this case, call to my_which should fail resulting in
script being aborted and thus avoiding this mess.
FIX
===
This utility my_print_defaults should be tested only in
Step 2 since it does not have an absolute path. Thus added
a condition in Step 1 so that is gets executed iff not
called for my_print_defaults thus bypassing it to proceed
to Step 2 where the check is made for various paths (in
$PATH)
During SST, since wsrep_sst_rsync waits for mysqld to create
"tables_flushed" file after it has successfully executed FTWRL,
it would wait forever if FTWRL fails.
Fixed by introducing a mechanism to report failure to the script.
If any given variable the xtrabackup-v2 sst script looks for is specified
multiple times in cnf file then it tend to pick both of them causing
some of the follow-up command to fail.
Avoid this programatic mistake by honoring only the last variable assigned
setting as done by mysqld too.
Check https://bugs.launchpad.net/percona-xtradb-cluster/+bug/1362830
Semantics:
---------
* Generally end-user will create a separate user with needed
privileges for
performing DONOR action.
* This user credentials are specified using wsrep_sst_auth.
* Along with this user there could be other user(s) created on the
server
that sysadmin may use for normal or other operations
* Credentials for these user(s) can be specified in same
cluster/server
cnf file as part of [client] section
When cluster act as DONOR and if wsrep_sst_auth is provided then it
should
strictly use it for performing SST based action.
What if end-user has same credentials for performing both SST action
and
normal admin work ?
* Then end-user can simply specify these credentials as part of
[client]
section in cnf file and skip providing wsrep_sst_auth.
Issue:
-----
MySQL client user/password parsing preference order is as follows:
* command line (through --user/--password)
* cnf file
* MYSQL_PWD enviornment variable.
Recent change tried passing sst user password through MYSQL_PWD
(and user though --user command line param as before).
On the system where-in admin had another user for performing non-SST
actions,
credentials for such user were present in cnf file under [client]
section.
Due to mysql client preference order, SST user name was used (as it
was
passed through command line) but password of other user (meant for
non-SST)
action was being used as it was passed through cnf file.
Password passed through MYSQL_PWD was completely ignored causing
user-name/password mismatch.
Solution:
---------
* If user has specified credentials for SST then pass them through
command
line so that they are used in priority.
(There could be security concern on passing things through command
line but
when I tried passing user-name and password through command line to
mysql
client and then did ps I saw this
./bin/mysql --user=sstuser --password=x xxxxxxxx -S /tmp/n1.sock
so seems like password is not shown)
- Add CA validation to wsrep_sst_xtrabackup-v2.sh.
- Also added a few {} around tpem for consistency.
- Abort if encryption is requested but socat is not ssl-enabled.
Patch contributed by : Klaas Demter
