I've got an app running Flask_sqlalchemy in a Docker container.
The container wasn't running properly so I dived in and tried running the application and get the following error:
sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) could not connect to server: Connection refused
Is the server running on host "DBNAME.XXXXXXXXXX.eu-west-1.rds.amazonaws.com" (000.000.000.000) and accepting
TCP/IP connections on port 5432?
The application works fine outside the container, and I can't work out what's going on.
Could it be something to do with the AWS-RDS security groups? They're currently configured to only accept inbound connections from our office where development takes place.
EDIT:
This is my Dockerfile:
FROM ubuntu:latest
RUN apt-get update -y
RUN apt-get install -y python-pip python-dev build-essential libpq-dev python-shapely
COPY . /src
WORKDIR /src
RUN pip install -r requirements.txt
EXPOSE 5000
CMD ["python", "application.py"]
And this is the Docker Run command I'm doing:
docker run -d -p 5000:5000 container_name
Thanks
I had exactly the same problem ;) but solved it by ensuring the following:
The AWS ELB environment configuration is Generic Docker (not preconfigured for Python).
The environment is created inside of a VPC that contains the RDS instance.
The RDS instance is listening to the right port (PostgreSQL:5432) from the VPC security group (this should already be the case).
Related
I wanted to launch a little static website on an EC2 instance and I followed the following steps:
launched a t2.micro instance using console in us-east-1 region
attached an existing security group which allows http request, https and ssh.
logged in my ec2 through SSH and changed it into an apache web server using following commands:
commands:
#bin/bash
sudo su
yum update -y
yum install httpd -y
cd /var/www/html
Then I wrote a hello world html code in index.html file and started my web service
service httpd start
chkconfig on
Even after following all the above steps, when I open try to access the webpage by going to the public ipv4 address of my ec2 instance, I am getting a timout error.
Any idea what I might be missing here?
Thank you.
You can try creating new EC2 instance like below
Lunch the same type of instance
Add below script in user data to create HTML page
#!/bin/bash
Use this for your user data (script from top to bottom)
install httpd
yum update -y
yum install -y httpd
systemctl start httpd
systemctl enable httpd
echo "Hello World - $(hostname -f)" > /var/www/html/index.html
After launching EC2, open that security group and add below HTTP rule
At the end, manually type HTTP://your public address. sometimes by default its shows with HTTPS so just ensure you are typing HTTP only.
I wrote a very simple spring-boot application and packed it in Docker.
The content of docker file is:
FROM openjdk:13
ADD target/HelloWorld-1.0-SNAPSHOT.jar HelloWorld.jar
EXPOSE 8085
ENTRYPOINT ["java", "-jar", "HelloWorld.jar"]
I pushed it to docker hub.
I created a new EC2 instance on aws. Then I connected to it and typed the following commands:
sudo yum update -y
sudo yum install docker -y
sudo service docker start
sudo docker run -p 80:8085 ****/docker-hello-world
The last command gave many messages on the screen that said that spring-boot application is running.
Looks great. However, when I opened my browser and typed: "http://ec2-54-86-87-68.compute-1.amazonaws.com/" (public DNS of EC2 machine).
I got "This site can’t be reached".
Do you know what I did wrong?
Edit: security groups that regard this machine are "default" and the following group that I defined:
Inside the EC2 machine, I typed:"curl localhost:8085" and got:
"curl: (52) Empty reply from server"
Ensure that your port's inbound traffic is enabled for your local IP address in your ec2 instance security group configuration
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-security-groups.html#adding-security-group-rule
Have you allowed inbound traffic for port 8085 in your security group configuration? That should be the first thing to check.
I found the solution.
It was port issues.
Instead of running
sudo docker run -p 80:8085 ****/docker-hello-world
I had to run:
sudo docker run -p 8085:8080 ****/docker-hello-world
This command says: "take the application that runs on port 8080 in the application and put it on port 8085 on docker".
I opened the browser and browsed to: "http://ec2-18-207-188-57.compute-1.amazonaws.com:8085/hello" and got the response I expected.
I have launch EC2 ubuntu instance and security group for this is instance allows 22,80,443 ports from 0.0.0.0/0.
Now i have installed docker on this EC2 instance.Then i have created an apache2 container and also mapped the port to access from browser using below command
sudo docker run -p 80:80 -t -i ubuntu /bin/bash
Then i create an lampstack conatiner and tried to map port using below command
sudo docker run -p 443:443 -t -i linode/lamp /bin/bash
Now docker ps gives me below
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS Name
d0751e67fd69 linode/lamp "/bin/bash" 4 min Up 4 0.0.0.0:443>443/tcp
affectionate_hamilton
0fb4e13a272a ubuntu "/bin/bash" 11 minutes 0.0.0.0:80->80/tcp
vigorous_robinson
When i take the public ip of my EC2 machine and put in browser i can see the apache page but how can i assess my Lampstack page ?
Please correct me if i have done port mapping incorrectly
You only need the LAMP container and in that one you should map the port 80:
sudo docker run -d --name lamp -t -p 80:80 linode/lamp top
Check that the container is up and running:
sudo docker ps --filter name=lamp
Now start the services:
sudo docker exec -ti lamp service apache2 start
sudo docker exec -ti lamp service mysql start
Test your setup from host:
curl http://localhost
If you want to test a connection from a different container you can start a separate ubuntu container that links to your original container "lamp":
docker run -ti --rm --link lamp --name ubuntu-box ubuntu bash
Inside the container install curl and test your connection:
apt update && apt-get install curl -y
curl http://lamp
I have a linux AWS instance. I am running the following script on it:
#!/usr/bin/env bash
#This script installs java, sbt and the application
#Run this script on a new EC2 instance as the user-data script, which is run by `root` on machine start-up.
sudo yum update -y
sudo yum install -y docker
sudo service docker start
docker run repo/carrie
Everything installs and I get the below message in the logs:
REST interface bound to /0.0.0.0:8080
However when I try to actually access the port like so:
curl 0.0.0.0/8080
I get the below message:
Failed to connect to 0.0.0.0 port 8080: Connection refused
I have tried editing the inbound rules so that 8080 is open but it doesn't seem to work. Maybe because I'm editing the rules after the instance has already launched?
You have to publish the container's port to the host in the docker run command
$ docker run --help
...
-p, --publish list Publish a container's port(s) to the host
...
The last line of your script should look like this if the process in the container listens on port 80:
docker run -p 8080:80 repo/carrie
The container gets its own interface, hence host's 0.0.0.0 is not applicable.
Tell docker to bind container port 8080 out to the host:
docker run -p 8080:8080 repo/carrie
I have a jenkins instance running inside a docker container that's listening on port 8181.
Example URL of the jenkins instance:
http://ec2-34-155-164-97.us-west-2.compute.amazonaws.com/
I have a tomcat docker instance that's listening on port 8383 running inside the jenkins docker container.
I can access jenkins instance from my local browser. Is there any possible way that I can access my docker tomcat instance from my local browser?
Here is my docker run command:
docker run -d -v /var/run/docker.sock:/var/run/docker.sock \ -v $(which docker):/usr/bin/docker -p 8181:8080 jenkins-dsl
Please provide your suggestions.
It sounds like your docker run command simply needs to expose the port that your nested tomcat server is running on.
To do this, you need to pass in -p argument into your command. The -p argument is for binding a host port to the docker container's port:
-p <host_port>:<container_port>
You can pass in as many -p arguments as you want to bind multiple ports.
So if the docker tomcat server is running on port 8383 within the Jenkins docker container, then you can do something like this:
-p 8383:8080
Full command example:
docker run -d -it -p 8383:8080 --name tomcatServer docker-tomcat
I would assume that this would allow you to access tomcat server using the example URL provided like so:
http://ec2-34-155-164-97.us-west-2.compute.amazonaws.com:8383
However, you'd have to ensure your AWS Security Group will allow traffic to port 8383.
EDIT: Updated answer to reflect the resolution we discussed in the comments.
Edited
I could able to launch tomcat by specifying the port in the URL and opening the port in EC2 instance.
http://ec2-34-155-164-97.us-west-2.compute.amazonaws.com:8383
Latest Docker installation guide for Tomcat clearly says you will get this error when you launch it for the first time
You can then go to http://localhost:8888 or http://host-ip:8888 in a browser (noting that it will return a 404 since there are no webapps loaded by default).
its because you do not have any apps in the default webapps folder of Tomcat. your latest Tomcat docker image has the default apps in the "webapps.dist" folder, you have to copy it to "webapps" folder. Do the Following commands
# docker exec -it tomcat-container /bin/bash
# cd webapps.dist
# cp -R * ../webapps
"tomcat-container" is your container name.
now refresh your browser you will get it. if not let me know