I have a Linux server (Debian 10, 16GB physical memory) with three docker containers running on it and two Java programs that perform financial calculations.

Docker containers:

• One is NGINX
• One is Database postgresql
• One is keycloak (authentification)

So nothing special.

Java-Programs:

These programs are started as follows. Note the -Xmx10g parameter:

./java/jdk/bin/java -Xmx10g -jar portal-backend-1.0-SNAPSHOT-runner.jar 2>&1 >> log/portal.log &

./java/jdk/bin/java -Xmx10g -jar pea-backend-1.0-SNAPSHOT-runner.jar 2>&1 >> log/pea.log &

SWAP-File:

Configuration of my 24GB swap-file:

fallocate -l 24G /swapfile

chown root:root /swapfile

sudo chmod 0600 /swapfile

Format swapfile:

mkswap /swapfile

Activate swapfile:

swapon /swapfile

In the file “/etc/fstab” added:

/swapfile swap swap defaults 0 0

When I now type swapon -s for status I get the following message:

Filename Type Size Used Priority
/swapfile file 25165820 0 -2

PROBLEM:

Even though I have activated a SWAP file, I get an out-of-memory exception. The interesting thing is that the SWAP file is always 0KB. It seems like it will never be attacked. What is wrong?

Attached a picture of htop shortly before I get the message Out-of-memory-Exception