Spring Boot Actuator Application Won't Start on Ubuntu Vps

Spring Boot Actuator application won't start on Ubuntu VPS

localhost-startStop-1 is trying to create a new instance of SecureRandom and it's stuck trying to read data from an entropy source. This typically occurs because the source has been depleted. The default entropy source is /dev/random. It's known as a blocking source as it will block when an attempt is made to read random data and none is available. Another source on Linux is /dev/urandom. Its main benefit over /dev/random is that it's non-blocking. There's some debate over whether or not using /dev/urandom will make things less secure. This article may be of interest.

In summary, using /dev/urandom will avoid the problem you're seeing, at the possible cost of decreased security. You can configure Spring Boot's embedded Tomcat instance to use /dev/urandom via a system property:

-Djava.security.egd=file:/dev/./urandom

How to deploy my Spring Boot application in these circumstances?

This solution applied to my hostgator VPS.
Consider:

ACCOUNT_NAME to be your account name;
DOMAIN_NAME to be your domain name. It can also be a subdomain;

1. Backup your apache settings:

cp -vp /etc/apache2/conf/httpd.conf{,-BKP}

2. Uncomment the lines of include in the vhost of the domain. Do it for the HTTP(std) and for the HTTPS(ssl):

vim /etc/apache2/conf/httpd.conf

3. Once you accessed the file, search the following lines and remove the #

Include
"/etc/apache2/conf.d/userdata/std/2_4/ACCOUNT_NAME/DOMAIN_NAME/.conf"
Include "/etc/apache2/conf.d/userdata/ssl/2_4/ACCOUNT_NAME/DOMAIN_NAME/.conf"

4. Create the following directories:

mkdir -p /etc/apache2/conf.d/userdata/std/2_4/ACCOUNT_NAME/DOMAIN_NAME
mkdir -p /etc/apache2/conf.d/userdata/ssl/2_4/ACCOUNT_NAME/DOMAIN_NAME

5. Create a .conf for std and ssl.

vim /etc/apache2/conf.d/userdata/std/2_4/ACCOUNT_NAME/DOMAIN_NAME/ACCOUNT_NAME.conf

vim /etc/apache2/conf.d/userdata/ssl/2_4/ACCOUNT_NAME/DOMAIN_NAME/ACCOUNT_NAME.conf

/etc/apache2/conf.d/userdata/std/2_4/ACCOUNT_NAME/DOMAIN_NAME/ACCOUNT_NAME.conf

RewriteEngine on
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
ProxyPass "/" "http://DOMAIN_NAME:10002/"

/etc/apache2/conf.d/userdata/ssl/2_4/ACCOUNT_NAME/DOMAIN_NAME/ACCOUNT_NAME.conf

ProxyPass "/" "http://DOMAIN_NAME:10002/"

8. Once you are done, restart the httpd service.

service httpd restart

Spring-boot application won't boot at startup inside docker

Got it! Once I installed haveged on the host, the process immediately moved forward, and spring booted fine. I will post more once I do a bit more research into how docker interacts with haveged on the host.

In summary the following command issued on the host will fix the the issue:

apt-get install haveged -y

If anyone has a detailed understanding of this, feel free to post!

The thing that I don't understand at the moment, is why the host machine needed extra code, and everything wasn't isolated within the docker container.

Spring Boot application as a Service

The following works for springboot 1.3 and above:

As init.d service

The executable jar has the usual start, stop, restart, and status commands. It will also set up a PID file in the usual /var/run directory and logging in the usual /var/log directory by default.

You just need to symlink your jar into /etc/init.d like so

sudo link -s /var/myapp/myapp.jar /etc/init.d/myapp

OR

sudo ln -s ~/myproject/build/libs/myapp-1.0.jar /etc/init.d/myapp_servicename

After that you can do the usual

/etc/init.d/myapp start

Then setup a link in whichever runlevel you want the app to start/stop in on boot if so desired.

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As a systemd service

To run a Spring Boot application installed in var/myapp you can add the following script in /etc/systemd/system/myapp.service:

[Unit]
Description=myapp
After=syslog.target

[Service]
ExecStart=/var/myapp/myapp.jar

[Install]
WantedBy=multi-user.target

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NB: in case you are using this method, do not forget to make the jar file itself executable (with chmod +x) otherwise it will fail with error "Permission denied".

Reference

http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/html/deployment-install.html#deployment-service

Problem running basic Spring Boot application

I tried to follow below steps in command line and worked successfully:

git clone https://github.com/spring-guides/gs-spring-boot.git

after cloning completed a new directory gs-spring-boot will be created then change directory to gs-spring-boot/initial

cd gs-spring-boot/initial

then run following command

./mvnw spring-boot:run

if you already have installed maven and available in your path instead you can use following command

mvn spring-boot:run

then spring application start to run after spring boot application start up finished without pressing Ctrl+c and terminating application switch to postman and point to address:

localhost:8080

then you will see expected result as below

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