JBoss WildFly 15.0.1 Final not starting on ubuntu 14.04 vServer with 2 GB: insufficient memory for JRE - wildfly

Question

I am trying to get JBoss WildFly 15.0.1 Final to start on a rather small ubuntu 14.04 vServer. The server has only 2 GB of RAM.
I tried to start WildFly many times without success. The JVM seems to require a lot more RAM than I had ever expected.
Here's the console output:
root#t2g55:~# service wildfly start
* Starting WildFly Application Server wildfly
* WildFly Application Server failed to start within the timeout allowed.
root#t2g55:~# cat /var/log/wildfly/console.log
=========================================================================
JBoss Bootstrap Environment
JBOSS_HOME: /opt/wildfly
JAVA: /usr/bin/java
JAVA_OPTS: -server -Xms768m -Xmx1536m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -Djava.net.preferIPv4Stack=true -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true
=========================================================================
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000000a0000000, 536870912, 0) failed; error='Cannot allocate memory' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 536870912 bytes for committing reserved memory.
# An error report file with more information is saved as:
# /opt/wildfly-15.0.1.Final/hs_err_pid1379.log
1379
root#t2g55:~# free
total used free shared buffers cached
Mem: 2097152 258748 1838404 64 0 38644
-/+ buffers/cache: 220104 1877048
Swap: 2097152 0 2097152
root#t2g55:~# java -version
openjdk version "1.8.0_222"
OpenJDK Runtime Environment (build 1.8.0_222-8u222-b10-1~14.04-b10)
OpenJDK 64-Bit Server VM (build 25.222-b10, mixed mode)
root#t2g55:~#
As you can see I specified JAVA_OPTS: -server -Xms768m -Xmx1536m ..., which I thought should suffice for a WildFly server to start. Please not, that the standalone.xml has a datasource defined to a MySQL DB.
Here's the start of the dump .log:
root#t2g55:~# cat /opt/wildfly-15.0.1.Final/hs_err_pid1379.log
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 536870912 bytes for committing reserved memory.
# Possible reasons:
# The system is out of physical RAM or swap space
# The process is running with CompressedOops enabled, and the Java Heap may be blocking the growth of the native heap
# Possible solutions:
# Reduce memory load on the system
# Increase physical memory or swap space
# Check if swap backing store is full
# Decrease Java heap size (-Xmx/-Xms)
# Decrease number of Java threads
# Decrease Java thread stack sizes (-Xss)
# Set larger code cache with -XX:ReservedCodeCacheSize=
# This output file may be truncated or incomplete.
#
# Out of Memory Error (os_linux.cpp:2757), pid=1379, tid=0x00007f62486c6700
#
# JRE version: (8.0_222-b10) (build )
# Java VM: OpenJDK 64-Bit Server VM (25.222-b10 mixed mode linux-amd64 compressed oops)
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
--------------- T H R E A D ---------------
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QUESTION:
Can this be solved with this amount of memory or do I simply have too few RAM?
What else could I probably try?
I don't really want my provider to go up with the mem successively only to find there's some other problem with Java, the JVM or anything...
Thanks
EDIT 1:
The vServer provider uses OpenVZ for its virtualization.
Info: they just pushed my to 4GB, then once, I got JBoss up and running. After reboot WildFly again refuses to start: same thing, not enough memory (even though I switch between Java 8 and Java 11 runtimes).
CMD to start JBoss WildFly: sh /opt/wildfly/bin/standalone.sh &, standalone.xml appears to be OK. I removed the ExampleDS, three entries commented.

Answer 1

It was indeed a server virtualization issue with OpenVZ.
Quote (in German):
Hi,
das Problem nach bei den user_beancounters, genauer gesagt bei privvmpages, diese waren > zu gering eingestellt.
https://wiki.openvz.org/UBC_secondary_parameters#privvmpages
Mit freundlichen Grüßen
Mr X
Translation:
Hi,
the problem was with the user_beancounters, that is with the privvmpages, these were set too low.
https://wiki.openvz.org/UBC_secondary_parameters#privvmpages
Best regards
Mr X
I don't know exactly what he did in detail, but that resolved it.
I now run on a 2GB machine without any problems and memory usage of mysqld + standalone.sh (WildFly + webapp) is around 800 MB.