nginx, Apache 2 and subversion – 502 Bad Gateway error

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. Setup There is a machine running nginx on port 80 (and 443 SSL) that serves as a reverse proxy for among other things…

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Reset Root Password on CentOS7

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…

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nginx: redirect to a new domain except part of the URL pattern

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…

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Install and use pdnsd for name service caching

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 Edit the /etc/pdnsd.conf file.  Under server, change the ip value to your DNS server. Edit the /etc/resolv.conf to point the server to itself. For my test, I commented out everything and only added the…

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Install and use ncsd for name service caching

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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Unable to update ca-certificates

Working on an early install of CentOS 6 and trying to update the system, the update failed. Even an attempt to update the ca-certificates failed. It turns out that the EPEL repository was the cause of this. To work past the offending EPEL repository and upgrade the ca-certificates, the following command works. Upon completion, a simple, yum update will work….

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MySQL

How to install a specific version of MySQL (or other app) via yum

To install an alternate version of, in this case, MySQL, rather than to accept the version that is available via the base and update yum repositories for CentOS, there are several ways of going about this.  You could install via tar.gz or download RPMs and yum install them directly; however, adding the official MySQL repository will work too.  It is…

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Use an RESL with SpamAssassin to Greatly Reduce Spam

Emailreg.org provides the Registered Email Send List (RESL) as a free lookup to anyone that would like to use it. It is also provided to those who have registered a domain here at EmailReg.org. The RESL is provided using a system that is similar to a DNS lookup. It is even more similar to a DNSRBL lookup. The RESL, however,…

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Add SMTP STARTTLS Support in Sendmail

Configure Sendmail email server to use SSL encryption for sending/receiving email. This is an example of using a CA certificate rather than a self-signed certificate.  This article assumes that the CA certificate is already in place and ready to go. Modify the /etc/mail/sendmail.mc file.  Find the section with similar variables that is commented out and copy this under it. At…

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Add Java JDK 8 Support to Confluence 5.6.1

Since the release of Atlassian Confluence 5.7, Java JDK 8 is officially supported. However, legacy versions of Confluence, in this particular case, version 5.6.1 is only officially supported through Java JDK 7.  From my reading only supported through Java JDK 7 Build 75. From java 7u767 and Java 8 onward, -Xloggc no longer accepts filenames with a “:” in it. …

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Create a logon banner in Linux

One file that may be edited is the /etc/motd file. To create a nice custom /etc/motd using ASCII / ANSI fonts, there is a little gem that can be installed on the local Linux box to allow you create some spectacular fonts, it is called figlet. Once you have added the epel repository to your system, it is as simple…

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How to Build the latest mod_jk RPM

mod_jk is an Apache module used to connect the Tomcat servlet container with web servers such as Apache. It has come increasingly difficult to find a an apache2-mod_jk-1.2.37-4.1.src.rpm or apache2-mod_jk-1.2.37-4.1.rpm as some of the links are now dead.  However, after tracking down a copy of the apache2-mod_jk-1.2.37-4.1.src.rpm, a modification or two to the .spec file along with the official .tar.gz…

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How to Build a Better haproxy RPM

There are several RPM builds of haproxy that can be found throughout the Internet.  There are GitHub repositories with customized .spec files to build your own RPM.  In fact, there is an haproxy.spec file that may be found in the official .tar.gz file under examples.  However, here is a unique way to build one as close to the original, haproxy-1.5.4-2.el6.rpm,…

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How to escape double quotes in sed

A recent attempt to replace a string within double quotes “string value” while using sed resulted in much trial and error. A quick Internet search revealed a working answer.  It is here for my reference. I wanted to replace “this value” with “that one” in a file, we’ll call testfile.  According to multiple sources, the sed command allows the use…

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SSLPoke Revisited

SSLPoke tests against the truststore to determine if it contains the right certificates.  It will let you connect to a SSL service, send a byte of input, and prints the response.  The tool should be simple enough to use, however, over the years there have been modifications made to it that effected it’s ability to simply work.  In some cases,…

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Install VMware tools on CentOS

There is a great deal of material on this subject.  However, this guide is a simplistic one for my reference.  If anyone should find it useful, that would be great too. Here are the steps to install VMware tools on Linux CentOS 6 and Linux CentOS 7. CentOS 6: Install VMware tools From within the VMware  vSPhere Client: From within…

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RDP into CentOS 7 with XRDP

From the man page, xrdp is a remote desktop protocol (RDP) server. Unlike Windows, xrdp will not display a Windows desktop but an X window desktop to the user. To install on a CentOS 7 Linux box with a GUI installed, turns out to be quite simple. A prerequisite will be the EPEL repository. yum install http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm Now that EPEL…

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