After installing Elasticsearch the application failed to start with a bootstrap error. ERROR: bootstrap checks failed max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536] max number of threads [1024] for user [username] is too low, increase to at least [2048] max virtual memory areas vm.max_map_count [65530] is too low, increase to at least…
Read More »There are several servers that seemed to be setup identically with a local user account called user1 which may be found using getent passwd user1. However, for one reason or another, the account had become inaccessible and returned an error. Although a reboot of the CentOS 6 server resolved the issue, I wanted to know more. It is Linux after…
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There is a CentOS 7 file server that is accessible and works well; however, the Microsoft Windows Network Neighborhood does not display it. After some digging around, there is a simple fix for that. Edit the /etc/samba/smb.conf file and under the [global] section add/modify the following lines to look like this. local master = yes os level = 34 Then…
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The history command is a command that I use daily. It can be used to list Bash’s log of the commands that you have typed. The results of that command include line numbers. Every now and again, it would be nice to execute history to retrieve a list without line numbers. This would greatly simplify the creation of script. it…
Read More »A CentOS 7 server running Icinga 2 was recently updated using yum update killed the service. The service simply did not restart. The reason turned out to be quite simple. The resolution is just as simple. According to the Icinga docs, upgrading Icinga 2 is usually quite straightforward. Ordinarily the only manual steps involved are scheme updates for the IDO…
Read More »This article details how to reset a forgotten MariaDB root password. I am not shedding any new light to this, this is here for a quick reference for me. The source of this excellent article is at the bottom of the page. Stop the service and start MariaDB in safe mode. service mariadb stop mysqld_safe –skip-grant-tables & There may be…
Read More »While performing yum updates on CentOS 7 minimal install virtual servers, I came across a problem server. The server needed a reboot after performing a hardware change. It did not come back up. It had a Kernel Panic error. I did so many things to that server, I didn’t know what the cause for the panic was, but fortunately I…
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After the much advertised Microsoft deadline of July 29, 2016 for the FREE Windows 10 upgrade had passed, it turns out that there is an extension for Windows 10 free upgrade for customers who use assistive technologies. This upgrade path is still valid as of September 22, 2016, so I thought I would upgrade a Dell i3 laptop from Windows…
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Although it is well documented that the Dell Latitude E6420 supports up to 8GB of RAM. Since memory prices have dropped over time, it was well worth the chance to upgrade the 8GB of RAM to 16GB of RAM. This may not work for everyone, but, it certainly worked on one Dell Latitude E6420 laptop. Using crucial.com the memory scanner…
Read More »There was a time when Microsoft Windows 95 ruled the scene. That time has come to pass a long time ago. However, while going through some 20 year old notes, I came across this little gem to upgrade a system that has Microsoft DOS 6.22 with Microsoft Windows 95 to Microsoft Windows 95B and keep the settings and files in…
Read More »Everyday with Linux there seems to be something new to learn or a little tidbit that is worth remembering. This time, the sysrq. Activates the System Request Key (aka. the Magic SysRq key), if thi value is set to anything other than zero (0), the default. sysrq The System Request Key allows immediate input to the kernel through simple key…
Read More »There are many articles that more than adequately detail a basic installation of the Windows Server Update Services (WSUS). This article assumes two things. The GPO has been configured and that this is a fresh installation of Windows Server 2012 with WSUS installed. No computers have connected yet. This article picks up at this point. Additional updates and configurations were…
Read More »All subversion checkouts, commits and other basic operations work as expected, but when attempting to copy, move or tag (copy) a (502 Bad Gateway) error presents itself. The error may be similar to the one presented below. greg@codemine:~/code/Foo (git-svn)-[trunk] %>; git svn tag foo-2.1.1 Copying https://svn/projects/Foo/trunk at r18311 to https://svn/projects/Foo/tags/foo-2.1.1… RA layer request failed: Server sent unexpected return value (502…
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CentOS7 offers a completely different approach to resetting a forgotten root password than the it’s earlier distro of CentOS6.x. Here are multiple approaches that was tested on CentOS Linux release 7.2.1511 (Core) with success. The last one being one that I combined from the many different approaches into fewer steps. Reset the Root password (version 1 Reboot the system to…
Read More »Migrating to newer version of a web application from one domain to another has had it’s challenges. Since this web application has multiple projects, each project may be migrated one at a time. The goal is to redirect traffic to the new projects as they are migrated to the new domain. As part of that goal, the projects that have…
Read More »The man pages describe pdnsd as a dns proxy daemon capable of saving the contents of its DNS cache to the disk on exit. The Install wget http://li.nux.ro/download/nux/misc/el6/x86_64/pdnsd-1.2.9a-par.x86_64.rpm yum install pdnsd-1.2.9a-par.x86_64.rpm cp /etc/pdnsd.conf.sample /etc/pdnsd.conf Edit the /etc/pdnsd.conf file. Under server, change the ip value to your DNS server. server { label= “myisp”; ip = 192.168.1.1,8.8.8.8; # Put your ISP’s DNS-server…
Read More »According to Red Hat, “[t]he Name Service Caching Daemon (nscd) is a service that runs in the background and keeps a copy of /etc/passwd, /etc/group, [/etc/netgroup, /etc/services] and /etc/hosts files in /var/db/nscd/ directory. This can aid performance by reducing disk read overhead on a heavily loaded system dealing with many logins or name resolution requests.” The installation and usage is…
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