Network Management

When aplying upgrade via gui as I always done without any problems, installation stops and says "cannot connect to database". I quit and after that the system is corrupt..? Some of the services wont start.

Running Red Hat Enterprise Linux Server release 7.5 (Maipo), with MySQL-server-5.6.27-1.el7.x86_64.

Any ideas? Cannot get any more details because I restored system from snapshot.

By the way, how is the installation procedure for MySQL now on RH 7, all guides seems outdated? I cannot find any newer MySQL-server-5.x.y1.el7.x86_64 for download as in HPE guides.. Tried to do a new installation on RH 7.6 with MySQL-server-5.x.y1.el7.x86_64 but i can't get Installation check to pass mysql connection check.

Hello,

Could be that you are running into the Timezone issue on Linux with MySQL.

Next time you attempt an upgrade, check the iMC\deploy\log\dmalog.txt and if you see any error like:

Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value 'CEST' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

Here is a workaround for now:

1) Login to MySQL command line (as root)
2) SET GLOBAL time_zone = '+3:00'; 
(where '+3:00' should be changed to this server's timezone offset) 

See also https://stackoverflow.com/questions/26515700/mysql-jdbc-driver-5-1-33-time-zone-issue

There is another issue that is triggered by NTA, if you have that module installed. It requires upgrading NTA to E0506P02 (to be released shortly).

That said, as I wrote in another post:

It would probably be better not to upgrade to E0703 if you haven't started already, unless you need the features/fixes. There are two known issues with RHEL and MySQL, and I posted the workarounds/fixes here (and in the other thread), and for one of them you would need the new NTA patch (to be posted).

There may be a new base version coming out relatively soon to address the known issues - but don't quote me on that as I'm not involved in it, and you would need to contact your HPE Sales/Account Management for any details about future versions.

Yeah, and @jguse really saved my day (reported issues -> doubt -> question -> issue avoided + waiting for updates)...read here...I'm on a scenario very similar to your one BUT, after reading all the issues that are popped up during last few days, I happily followed given advice.

Hi again. In preparation for the upcoming release i try to set up a new platform with release 7.3 E0605P06 on i new installed RH 7.5 server. Following the MySQL 5.6 on Redhat guide. Everything seems ok, i can connect to database via  mysql –u root –p. So far so good.

But when i trying to install iMC I got database connection error and cannot continue installation. I tried with iMC 7.1, 7.2, 7.3, E403, E506, But with the same error. 

So what the hell am I doing wrong? I have worked with this for days now and cannot understand what's wrong. Also tried other versions of MySQL and RH, but same problem.

Any ideas?

Hello,

There's one key bit of information I noticed is missing in the manual (sorry, I'd update it if I could). The hostname and actual IP address of the IMC server must be defined in /etc/hosts for IMC installation to work.

Edit /etc/hosts and add a line with "imc.my.domain ip.address", save and try the IMC installer again.

Here is a video on the whole installation process that should help: https://www.youtube.com/watch?v=Ymz-I9F4Hko

Hope that helps you get it running...

Thanks, I'll try that and reply with info soon. Another thing. What value shold it be in the timezone for Central European time in below description:

1) Login to MySQL command line (as root)
2) SET GLOBAL time_zone = '+3:00'; 
(where '+3:00' should be changed to this server's timezone offset) 

Hello,

Here are some MySQL-related answers about timezone that should provide clarity:

https://stackoverflow.com/questions/5488694/mysql-difference-between-cet-and-cest

https://stackoverflow.com/questions/930900/how-do-i-set-the-time-zone-of-mysql

If you are on CET, that is UTC+1:00 and the timezone offset should be based on UTC offsets (not GMT).

Thanks. I notice that there are problems installing  MySQL-server-5.6.27-1.el7.x86_64.rpm on RH 7.6. Which version do you recommend for RH 7.6? 

Seems ok on earlier versions, like RH 7.4

It does not seem to install properly.

[root@x5377 ~]# service mysql start
Starting MySQL.. ERROR! The server quit without updating PID file (/var/lib/mysql/x5377.svk.local.pid).
[root@x5377 ~]#

Are there any details about the error? For example with service mysql status output, or looking in /var/lib/mysql/ for any .err files that were generated.

I wonder if there is a restriction in RHEL 7.6 regarding MySQL versions supported? However MySQL indicates it should be supported: https://www.mysql.com/support/supportedplatforms/database.html

[root@x5377 dasi]# service mysql status
ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql) exists

[root@x5377 dasi]# more /var/lib/mysql/x5377.svk.local.err

2019-06-20 12:34:38 8407 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
2019-06-20 12:34:38 7f8cc046b780 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed
in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
2019-06-20 12:34:38 8407 [Note] InnoDB: Using atomics to ref count buffer pool pages
2019-06-20 12:34:38 8407 [Note] InnoDB: The InnoDB memory heap is disabled
2019-06-20 12:34:38 8407 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2019-06-20 12:34:38 8407 [Note] InnoDB: Memory barrier is not used
2019-06-20 12:34:38 8407 [Note] InnoDB: Compressed tables use zlib 1.2.3
2019-06-20 12:34:38 8407 [Note] InnoDB: Using Linux native AIO
2019-06-20 12:34:38 8407 [Note] InnoDB: Using CPU crc32 instructions
2019-06-20 12:34:38 8407 [Note] InnoDB: Initializing buffer pool, size = 512.0M
2019-06-20 12:34:38 8407 [Note] InnoDB: Completed initialization of buffer pool
2019-06-20 12:34:38 8407 [Note] InnoDB: Highest supported file format is Barracuda.
2019-06-20 12:34:38 8407 [Note] InnoDB: Log scan progressed past the checkpoint lsn 49463
2019-06-20 12:34:38 8407 [Note] InnoDB: Database was not shutdown normally!
2019-06-20 12:34:38 8407 [Note] InnoDB: Starting crash recovery.
2019-06-20 12:34:38 8407 [Note] InnoDB: Reading tablespace information from the .ibd files...
2019-06-20 12:34:38 8407 [Note] InnoDB: Restoring possible half-written data pages
2019-06-20 12:34:38 8407 [Note] InnoDB: from the doublewrite buffer...
InnoDB: Doing recovery: scanned up to log sequence number 1600607
2019-06-20 12:34:38 8407 [Note] InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percent: 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
InnoDB: Apply batch completed
2019-06-20 12:34:39 8407 [Note] InnoDB: 128 rollback segment(s) are active.
2019-06-20 12:34:39 8407 [Note] InnoDB: Waiting for purge to start
2019-06-20 12:34:39 8407 [Note] InnoDB: 5.6.27 started; log sequence number 1600607
2019-06-20 12:34:39 8407 [Note] Server hostname (bind-address): '*'; port: 3306
2019-06-20 12:34:39 8407 [Note] IPv6 is available.
2019-06-20 12:34:39 8407 [Note] - '::' resolves to '::';
2019-06-20 12:34:39 8407 [Note] Server socket created on IP: '::'.
2019-06-20 12:34:39 8407 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.user' doesn't exist
190620 12:34:39 mysqld_safe mysqld from pid file /var/lib/mysql/x5377.svk.local.pid ended

Some mor information here. envcheck.sh:

[root@test install]# ./envcheck.sh
InetAddress.getLocalHost():test/192.168.145.134
InetAddress.getLocalHost():test/192.168.145.134
InetAddress.getLocalHost():test/192.168.145.134
InetAddress.getLocalHost():test/192.168.145.134
InetAddress.getLocalHost():test/192.168.145.134
InetAddress.getLocalHost():test/192.168.145.134
Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
oracleHome is null
MySQL Installed
Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
oracleHome is null
MySQL Installed
java.io.FileNotFoundException: ./components/common/deploy/custom/custom.properties (No such file or directory)
Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
java.io.FileNotFoundException: ./components/common/deploy/custom/custom.properties (No such file or directory)
flag is true
className:com.mysql.jdbc.Driver
URL: jdbc:mysql://127.0.0.1:3306/
user = root
password = 123456QA
Execute 'mysql -V', return: 0
STDOUT: mysql Ver 14.14 Distrib 5.6.44, for Linux (x86_64) using EditLine wrapper

STDERR:
Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
Change LD_LIBRARY_PATH=./:/root/linux/install/common/jre_linux64/lib/amd64/server:/root/linux/install/common/jre_linux64/lib/amd64:/root/linux/install/common/jre_linux64/../lib/amd64
Execute 'conntest' failed
java.io.IOException: Cannot run program "/tmp/1561046843997/common/lib/conntest_my_linux" (in directory "/tmp/1561046843997/common/lib"): java.io.IOException: error=2, No such file or directory
at java.lang.ProcessBuilder.start(ProcessBuilder.java:470)
at java.lang.Runtime.exec(Runtime.java:593)
at com.h3c.imc.deploy.Util.executeCommand(Util.java:3997)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog.a(DatabaseSelectPanelDescriptor.java:2246)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog.doWork(DatabaseSelectPanelDescriptor.java:2123)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog.doWork(DatabaseSelectPanelDescriptor.java:1787)
at com.h3c.imc.deploy.wizard.WorkingDialog$a.doInBackground(WorkingDialog.java:282)
at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:316)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.IOException: java.io.IOException: error=2, No such file or directory
at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
at java.lang.ProcessImpl.start(ProcessImpl.java:65)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:452)
... 13 more
flag is true
modifySSLReg is false
rebootFlag is false
未修改套接字
dhcp及eventlog服务重启成功了
canGoon is false

And from log: more /etc/iMC-Reserved/log/install_20190620175449.txt

2019-06-20 17:54:49 [WARN ] [main] [com.h3c.imc.deploy.Util::getInstallInfo(864)
] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:49 [WARN ] [main] [com.h3c.imc.deploy.Util::getInstallInfo(864)
] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:49 [WARN ] [main] [com.h3c.imc.deploy.Util::getInstallInfo(864)
] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:49 [INFO ] [main] [com.h3c.imc.deploy.InstallLauncher::checkEnv
(297)] Deploy jar file not found, first installation
2019-06-20 17:54:49 [WARN ] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::getInst
allInfo(864)] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:57 [INFO ] [AWT-EventQueue-0] [com.h3c.imc.deploy.install.wizar
d.AgreementPanel::b(178)] getAgreementText
2019-06-20 17:54:57 [ERROR] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::g(2962)
] java.io.FileNotFoundException: ./components/common/deploy/custom/custom.proper
ties (No such file or directory)
2019-06-20 17:54:57 [INFO ] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::getCust
omStringWithOemInfo(3002)] agreementPanel.fileName has no custom value
2019-06-20 17:54:57 [INFO ] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::getCust
omFolderName(3028)] path:./components/common/deploy/custom
2019-06-20 17:54:57 [WARN ] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::getInst
allInfo(864)] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:57 [WARN ] [AWT-EventQueue-0] [com.h3c.imc.deploy.Util::getInst
allInfo(864)] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.Util::checkReservedPo
rt(1916)] InetAddress.getLocalHost():test/192.168.145.134
2019-06-20 17:54:57 [WARN ] [Thread-2] [com.h3c.imc.deploy.Util::getInstallInfo(
864)] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.dma.wizard.DatabaseSe
lectPanelDescriptor::isOracleInstalled(1484)] oracleHome is null
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.dma.wizard.DatabaseSe
lectPanelDescriptor::isMySQLInstalled(1608)] MySQL Installed
2019-06-20 17:54:57 [WARN ] [Thread-2] [com.h3c.imc.deploy.Util::getInstallInfo(
864)] Can not find instInfoFile - /etc/iMC-Reserved/instinfo.txt
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.dma.wizard.DatabaseSe
lectPanelDescriptor::isOracleInstalled(1484)] oracleHome is null
2019-06-20 17:54:57 [INFO ] [Thread-2] [com.h3c.imc.deploy.dma.wizard.DatabaseSe
lectPanelDescriptor::isMySQLInstalled(1608)] MySQL Installed
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::doWork(20
59)] flag is true
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::doWork(20
71)] className:com.mysql.jdbc.Driver
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::doWork(20
74)] URL: jdbc:mysql://127.0.0.1:3306/
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::doWork(20
76)] user = root
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::doWork(20
76)] password = Xtp39LqX
2019-06-20 17:55:03 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::c(2322)]
Execute 'mysql -V', return: 0
STDOUT: mysql Ver 14.14 Distrib 5.6.44, for Linux (x86_64) using EditLine
wrapper

STDERR:
2019-06-20 17:55:04 [INFO ] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::b(2298)]
Change LD_LIBRARY_PATH=./:/root/linux/install/common/jre_linux64/lib/amd64/serve
r:/root/linux/install/common/jre_linux64/lib/amd64:/root/linux/install/common/jr
e_linux64/../lib/amd64
2019-06-20 17:55:04 [ERROR] [SwingWorker-pool-1-thread-1] [com.h3c.imc.deploy.dm
a.wizard.DatabaseSelectPanelDescriptor$DbConnectCheckingWorkingDialog::a(2268)]
Execute 'conntest' failed
java.io.IOException: Cannot run program "/tmp/1561046103731/common/lib/conntest_
my_linux" (in directory "/tmp/1561046103731/common/lib"): java.io.IOException: e
rror=2, No such file or directory
at java.lang.ProcessBuilder.start(ProcessBuilder.java:470)
at java.lang.Runtime.exec(Runtime.java:593)
at com.h3c.imc.deploy.Util.executeCommand(Util.java:3997)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnect
CheckingWorkingDialog.a(DatabaseSelectPanelDescriptor.java:2246)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnect
CheckingWorkingDialog.doWork(DatabaseSelectPanelDescriptor.java:2123)
at com.h3c.imc.deploy.dma.wizard.DatabaseSelectPanelDescriptor$DbConnect
CheckingWorkingDialog.doWork(DatabaseSelectPanelDescriptor.java:1787)
at com.h3c.imc.deploy.wizard.WorkingDialog$a.doInBackground(WorkingDialo
g.java:282)
at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:316)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:918)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.IOException: java.io.IOException: error=2, No such file or di
rectory
at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
at java.lang.ProcessImpl.start(ProcessImpl.java:65)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:452)
... 13 more
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(432)] flag is
true
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(438)] modifySS
LReg is false
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(439)] rebootFl
ag is false
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(447)] 未修改套
接字
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(450)] dhcp及ev
entlog服务重启成功了
2019-06-20 17:55:06 [INFO ] [Thread-2] [com.h3c.imc.deploy.u::run(479)] canGoon
is false

Update and solution:

It was my fault all the time... Mixed up x86_64 with i686 on the pakets:

rpm -i --nodeps glibc-2.17-222.el7.x.i686.rpm
rpm -i --nodeps libaio-0.3.109-13.el7.i686.rpm
rpm -i --nodeps libgcc-4.8.5-28.el7.i686.rpm
rpm -i --nodeps libstdc++-4.8.5-28.el7.i686.rpm
rpm -i --nodeps nss-softokn-freebl-3.34.0-2.el7.i686.rpm

Installed them and all ok.

But it is aproblem with RH 7.6:

nss-softokn-freebl-3.34.0-2.el7.i686.rpm cause problems with nss-softokn-freebl-3.34.0-2.el7.x86_64. Did not solve that issue. Works fine on RH 7.5.

Database used is mysql-community-server-5.6.44-2.el7.x86_64.

Followed this install guide: https://www.linode.com/docs/databases/mysql/how-to-install-mysql-on-centos-7

  On that one I need to maually do this:

mysql -u root -p
show variables like "max_connections";
set global max_connections = 600;

After that everything works fine. Thanks for all help!

I can also conffirm that CentOS 7.5 works fine.

Ah, glad to hear you could get it working!

Technically you should use MySQL Enterprise (according to Release Notes), but I'll admit I've used the community edition myself for some lab installs and it works fine. Since you mention my.cnf, here is a config I made for reference that is working for me on 5.6, using 1000 max connections to ensure IMC has enough if you install optional modules:

# This file has all unnecessary comments and options removed.
# For all options, please look at the original my-huge.cnf file.

[client]
port = 3306
socket = /var/lib/mysql/mysql.sock

[mysqld]
port = 3306
socket = /var/lib/mysql/mysql.sock
skip-external-locking
key_buffer_size = 384M
max_allowed_packet = 200M
table_open_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size = 32M
max_connections = 1000
character-set-server = latin1
default-storage-engine = INNODB
lower_case_table_names = 1
innodb_buffer_pool_size = 512M
innodb_additional_mem_pool_size = 16M
thread_concurrency = 8
server-id = 1

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

I recall having issues with 5.7 because IMC requires innodb_additional_mem_pool_size which is deprecated there. Perhaps they've removed that requirement in E0703 though, I'll make a note to test it one of these days.

True, there is a problem with 5.7. Confirmed. I said to HPE support to update docs or provide a fix so it won't be any missunderstandings.

I also encountered problems with max_connections. on mysql-community 5.6:

You need to do this to make max connections persist:

vi /etc/systemd/system/mysql.service
Add to the bottom:
LimitNOFILE=infinity
LimitMEMLOCK=infinity

systemctl daemon-reload
systemctl restart mysql

Hi again. Sorry but the etc/hosts file editing dit not help. What else could it be?