Category Archives: DataCenter

#OpenSSH private keys with old PEM format

Starting from openssh 7.8 the default format for private keys has changed from PEM to OpenSSH: That means that private keys generated with the referenced command: (ssh-keygen -t rsa -b 4096) are no longer generated as PEM format. Lot’s of online services do not accept this format yet CircleCI, GitHub are some of the services… Read More »

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Disable core dumps in #Linux

Systemd doesn’t completely control whether core dumps are made or not. It mainly determine where such dumps go, and whether they should take up space or not. It may prevent some user space core dumps, but not all. With “Storage=none”, they can still occur and are registered by journald, but they don’t take up disk… Read More »

Use #letsencrypt to generate a wildcard domain certificate

I am an old user of letsencrypt that just found out that my old way of renewing my set of certificated is no longer supported. When running the usual “certbot renew” command, that was manually renewing my certificates, resulted in the error: 2019-04-06 17:38:19,072:WARNING:certbot.renewal:Attempting to renew cert (blog.voina.org) from /etc/letsencrypt/renewal/blog.voina.org.conf produced an unexpected error: Client… Read More »

Convert text label files to UTF-8 encoding

In a lot of multi-language enterprise applications where you have to support labels in different languages the text files with the different labels for each language are scattered across your source code. In my case I all the labels are kept in Java property files with “.properties” file extension. Then for each language I have… Read More »