static hostname on a ubuntu EC2 instance
Related cards:
HowTo: enable termination protection for all EC2 instances not in autoscaling groups via aws cli
aws ec2 describe-instances --output text --query 'Reservations[].Instances[?!not_null(Tags[?Key == `aws:autoscaling:groupName`].Value)] | [].[InstanceId]' | xargs -L1 -t aws ec2 modify-instance-attribute --disable-api-termination --instance-id...
Why Apple Silicon MacBooks Can Only Use One External Display Through A Dock
It's quite confusing how many external displays are usable with a MacBook that uses an M1 or M2 Chip. Documentation on the Internet is sparse and not even the Geniuses at the Genius Bar are 100% sure. We found out some things and can explain the b...
Capistrano 3: assets:precompile only on one server
Disclaimer
This should not be necessary in any case and is only for special cases, for e.g. if the assets directory is linked to a shared storage (for e.g. glusterfs). Please mind that it isn't wise to move your assets directory to a shared s...
FAQ for When PostgreSQL Indexes Are Corrupted After Locale Changes
When changing glibc versions, it's possible to end up with corrupt indexes in PostgreSQL.
Are My Indexes Affected?
If your database has...
Installing throttled to fix Lenovo laptops with nvidia graphics running Ubuntu losing performance after a while
We have observed Lenovo laptops with nvidia graphics losing performance after they have been in use for a few minutes. While we have not been able to pinpoint exactly what triggered the performance loss, we have found it mostly correlated with hig...
Keepalived VRRP FAQ
How can I configure virtual IP's?
There are two parameter to set up virtual ips in Keepalived:
virtual_ipaddress
Addresses defined here are included into the VRRP Packages and are therefore limited in number, especially with IPv6.
Add...
How to Protect container images with production tag from ECR lifecycle rules
If you want to automatically delete old container images from your Elastic Container Registry, the solution is a quite simple ECR Lifecycle Rule that deletes images e.g. 7 days after they have been pushed to the registry.
If you however want to _...
Elasticsearch unassigned replica shards on single node instances
If you have a single node elasticsearch instance and indices with replicas enabled your cluster state will be yellow. If you have replica shards they should be moved to a different node for high availability purposes. With a single node this can't...
HowTo: Curl applications that are usually behind reverse proxies with TLS termination without the application redirecting to https schema
A lot of web applications require being called over https, which is a good thing. It's possible to configure this requirement at the web- or proxy server level, where nginx or apache will just redirect every request on http to https. Som...
HowTo: Downgrade a Port on FreeBSD
Example
collectd5 in version 5.9.0 is broken and you upgraded it everywhere. But because it's FreeBSD it does not restart running services. After every old version is removed from /var/cache/pkg you restarted collectd and it does not s...
