Mysql replication

Had to resync master-slave replication setup. Here are my notes on how it’s done.

Binary bin-log files are kept for 7 days on DB1. If the replication is stopped for more than a week DB2 replication cannot start again due to the binary log files is no longer available. therefor a fresh dump is needed and DB2 replication can be started again from the master log position.



  • Single-transaction, makes it possible to do the dump without locking the database, very useful when having to dump from a production database. But while not locking the DB you may not create or alter table schema.  Mysql documentation link
  • master-data, is very useful because it records the master position when doing the dump and putting it into the output of the dump file. Therefore it is much easier to start the slave from the correct position. The number 2 is for only printing it to the output as a comment. Mysql documentation link
  • event and routines, if there are any stored procedures or like in the old server we take them with us. Mysql documentation link

mysqldump --single-transaction --quick --master-data=2 --events --routines <DATABASE> | gzip > /data/<DATABASE> _`date +%F`.sql.gz

When the dump is done we move the dump file over to the other server. Here we import it to the MySQL server if there already were an old database in place, drop it and create it again.
zcat <DATABASE>.sql.gz | mysql <database>

Also, have a look at the head of the dump file where we will find the master position data that we need to start the replication again.

gzip -cd <DATABASE>.sql.gz | head -n24

Now we have the position and need the user for replication. I did it on an older 5.5 database, in newer MySql servers it is done differently.


Or if the user is in place and you just need to reset the password:

When it is imported we need to setup the master to master(slave) replication again. Remember to have a user on DB1 that is allowing replication from the DB2 server and have the user and password ready CHANGE MASTER TO MASTER_HOST='<IP>',MASTER_USER='repl', MASTER_PASSWORD='happyS3ed99', MASTER_LOG_FILE='mysql-bin.000849', MASTER_LOG_POS=758329777 ;

It will now start to replicate from the master, now you can do a “mysql -e ‘show slave status\G'” and see if the slave IO is running as it should.


Rescuing a Juniper SRX550

Notthing more greate than getting a call from HQ 30 minutes after closing hours. Never the less i decided to take the call. Network problem onsite at customer…. After getting green light from women in charge, i got in the car an when on to the customer.

Connection with the USB cable to the SRX console port i got a weird boot sequence. Just like the following:

>U-Boot 1.1.6-JNPR-2.7 (Build time: Nov 26 2013 - 19:04:49)

Initializing memory this may take some time...
Measured DDR clock 533.33 MHz
SRX_550 board revision major:1, minor:18, serial #:
OCTEON CN6335-AAP pass 2.2, Core clock: 1300 MHz, DDR clock: 533 MHz (1066 Mhz data rate)
DRAM:  2048 MB
Starting Memory POST...
Checking datalines... OK
Checking address lines... OK
Checking 512K memory for U-Boot... OK.
Running U-Boot CRC Test... OK.
Flash:  8 MB
USB:   scanning bus for devices... 1 USB Device(s) found
       scanning bus for storage devices... 0 Storage Device(s) found
Clearing DRAM...... done
BIST check passed.
PCIe: Initializing port 1
PCIe: Port 1 link active, 1 lanes, speed gen1
Boot Media: usb internal-compact-flash
Net:   octeth0

  ide 0: Model: CF CARD  Firm: Ver7.01K Ser#:
            Type: Removable Hard Disk
            Capacity: 3811.9 MB = 3.7 GB (7806960 x 512)

Warning!!!  SSD not detected
POST Passed
Press SPACE to abort autoboot in 1 seconds
ELF file is 32 bit
Loading .text @ 0x8f0000a0 (246560 bytes)
Loading .rodata @ 0x8f03c3c0 (14144 bytes)
Loading .reginfo @ 0x8f03fb00 (24 bytes)
Loading .rodata.str1.4 @ 0x8f03fb18 (16516 bytes)
Loading set_Xcommand_set @ 0x8f043b9c (96 bytes)
Loading .rodata.cst4 @ 0x8f043bfc (20 bytes)
Loading .data @ 0x8f044000 (5744 bytes)
Loading .data.rel.ro @ 0x8f045670 (120 bytes)
Loading .data.rel @ 0x8f0456e8 (136 bytes)
Clearing .bss @ 0x8f045770 (11600 bytes)
## Starting application at 0x8f0000a0 ...
Consoles: U-Boot console
Found compatible API, ver. 2.7

FreeBSD/MIPS U-Boot bootstrap loader, Revision 2.7
(ccheng@svl-junos-d081.juniper.net, Tue Nov 26 19:05:43 PST 2013)
Memory: 2048MB
[1]Booting from internal-compact-flash slice 1
Un-Protected 1 sectors
writing to flash...
Protected 1 sectors

can't load '/kernel'
can't load '/kernel.old'
Press Enter to stop auto bootsequencing and to enter loader prompt.

U-Boot 1.1.6-JNPR-2.7 (Build time: Nov 26 2013 - 19:04:49)

Initializing memory this may take some time...

Either the Junos partition was corrupt or the disk inside of the unit was fried. Decided to try and install Junos again just see if that would help. Went to juniper.net and downloaded the oldest Junos version available, junos-srxsme-12.3X48-D10.3-domestic.tgz. Found a USB drive and put the .tgz file on it and plugged it in the SRX. From the console i broke the bootloader while its was trying to find kernel and issued the following command.


I began to install Junos, but when it tried to create partitions on the card, it died with DMA errors. Great!

Since a SRX550 is not something you find everyday and spareparts a hard to get (support was also expired) i decided to take the srx apart. happily to find a CF card inside and luckily i found a kingstone CF card in my bag (I knew that would come in handy someday). Swapped the card and put it together again.

Power on and issued the install command again. This time with success.

The install of Junos take sometime, a long time 20 minutes. But then you also get a very nice login prompt. logged in with root and no password. Went into cli configuration mode and did a “delete” to wipe the factory config. then loaded the backup configuration with

load overwrite terminal

Pasted the 55kb JSON config into the console and finished with a ctrl+d followed by a commit. commit success and all network was suddenly alive again.

just to make all the LEDs green on the SRX i did wrote the config to rescue config. This is in operational mode.

request system configuration rescue save

A happy consumer and hopefully a new Juniper SRX1500 firewall on its way to relive the SRX550 off its duties.


PowerCLI – View host HA status

Had a minor problem with a host that was not able to configure HA agent after a vCenter update, 6.5 build 15000 to build 21000. It was the only host in the cluster that had the error.

– set the host in and out of maintenance mode and to move the host out and in of the cluster. Did not help.
– disable and enable of HA on cluster level work for all the other host, but not my stubborn one.

Reading a VMware 2056299 told me to manuel uninstall the HA vib (vmware-fdm) with

esxcli software vib remove -n vmware-fdm

After successfully uninstall i took the host out of maintenance and did a Disable/enable HA on cluster level, and volia it now works.

GUI is always a bit slow to update, but with PowerCLI you get current status.

PS C:\> $clusterName = "Cluster1"
PS C:\> Get-Cluster -Name $clusterName | Get-VMHost | Select Name,@{N='State';E={$_.ExtensionData.Runtime.DasHostState.State}}


Import certificate to NSX Edge

Normally when I get a certificate from a customer I often get it in PFX format, but NSX Edge wants it in PEM format. What often is confusing here is that the when converting the PFX the private key gets out in the PKCS8 format but Edge wants the private key in PKCS1 format.

Here is a write-up of the conversion. You will need OpenSSL on the machine that you work on windows, UNIX or macros doesn’t matter.

First, we will need to spit the PFX into .crt and .key with these two commands

openssl pkcs12 -in [yourfile.pfx] -nocerts -out [private.key]
openssl pkcs12 -in [yourfile.pfx] -clcerts -nokeys -out [certificate.crt]

Now we need to convert the private.key from PKCS8 to PKCS1 format with this command

openssl rsa -in private_pkcs8.key -out private_pkcs1.key

Now you can go to your NSX Edge and import the certificate with .crt and pricate_pkcs1.key files

Later on, I have found that I need to import the certificate with the intermediate certificate of the signing 3. party. In my case its GoDaddy.
To do this we convert the certificates to .PEM and afterward.

.\openssl pkcs7 -print_certs -in gd-g2_iis_intermediates.p7b -out gd-interm.pem

Then we can convert the cert to pem and put the two certificates in the same file.

openssl x509 -in hk-domain.dk.crt -out hk-domain.dk.pem -outform PEM

Now you can paste this into the load balancer. There must be an easier way to do it, if you find one then please ping me.

Edit: Found a couple of other OpenSSL commands that I from time to time struggle to find.

# Convert unencrypt pem cert:
openssl rsa -in file1.key -out file2.key
# Convert pkcs7 to pem format:
openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer