Recently I am reading the book “SQL The Complete Reference” to refresh the SQL language of the RDMS. I find that the SQL syntax diagram, sometimes also called SQL railroad, helps a lot in understanding the structure of the SQL… Read More
find package owning a specific file in ubuntu
I am familiar with the rpm package management system, because the products in our company are running in the RHEL Linux OS and the development in my daily work sometimes involves manipulating rpm packages, for example, installing, uninstall, searching rpm… Read More
nginx proxy_request_buffering
Yesterday, I was assigned a bug, in which uploading a file caused a ‘401 unauthorized’ error response. After analyzing this issue, I found that it took about 10 minutes to upload a file. The long time was caused by network… Read More
Nodejs JavaScript heap out of memory
Yesterday when I tried to build my react application, I got the below error message in the console: FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed – JavaScript heap out of memory 1: 0x8dc510 node::Abort() [node] 2: 0x8dc55c [node]… Read More
remove node from Kubernetes cluster safely
Confirm the name of the node you want to remove, and make sure that the pods on the node can be terminated. The pod list can be retrieved using the below command: kubectl get nodes Mark the node as unschedulable… Read More
ssh port forwarding in practice
As a global company, it is very common that a server in one site needs to communicate with another server in another site. These days we encounter this situation: a server named A in China, assuming IP 192.168.10.10, needs to… Read More
serve static content using springboot
springboot can serve static content files, for example, html, js, css and image, for http request. By default, springboot searches the below directories for the static resources in the class path. classpath:/META-INF/resources/ classpath:/resources/ classpath:/static/ classpath:/public/ So you can put your… Read More
create self-signed certificate with san
I explained why google chrome browser does not respect a certificate without Subject Alternative Name in my earlier post. I also showed how to create a self-signed certificate using a single openssl command, but that certificate did not include SAN.… Read More
nvm introduction
nvm is an excellent tool that can be used to manage different versions of nodejs in a single OS. I am using nvm in my development Linux server to switch the nodejs to the latest version after I download it… Read More
chrome does not use commonName to verify site certificate
I showed how to create a self-signed certificate using openssl command line in this post. However, after I created a self-signed certificate using the similar openssl command and deployed the certificate in a Kubernete ingress, I always got a warning… Read More