I am trying to setup a Docker swarm which connects 3 of my servers together. The swarm is setup and going to the URL I get the same result, which is perfect and just what I need.
However, for the server in which I am working on now I am producing a global nginx on every server in order to allow load balancing.
Sitting on the server will be multiple config files which I need in order to map the domain to the correct folder, which is the part which I am stuck on/not working for me.
I have a really simple docker-compose.yml as I have shrunk it in order to debug the issue, it consists of the following...
version: '3'
services:
nginx:
image: nginx:latest
volumes:
- /var/www/nginx/config/:/etc/nginx/conf.d/:ro
deploy:
mode: global
The volume is coming back with the error "invalid mount config for type "bind": bind source path does not exist" so obviously when I remove the volume line it works perfectly, however I 100% need this line.
I can, inside of the server navigate perfectly to /var/www/nginx/config/ and my config files exist within. Same with the other, if I run docker exec -it <container> /bin/bash and navigate to /etc/nginx/conf.d I can get to there perfectly fine which is why I'm posting on here.
I've looked at other posts and done what other people have said have fixed it such as
Adding quotes to the volume
Remove the slash at the end of the file
Restart the server
Restart Docker
But nothing seems to be working
The potential issue could be that not all the nodes in your swarm cluster have the directory (/var/www/nginx/config/) created. Since in swarm the service can be placed in any of the available nodes(unless you put in a constraint) you might be seeing this error.
Make sure that you have this directory created in all the 3 nodes.
Additionally you can also have a look here for defining configs.
Related
It's been a few days since I've been trying to get docker container up and running, and always something goes wrong.
I need (mostly) LAMP stack, only instead MySQL -> mongoDb.
Of course I started by looking on docker hub and trying to compose some image from others. Googled after configs. Simplest one couldn't go past the stage of setting MONGODB_ADMIN_USER and MONGODB_ADMIN_PASSWORD and always returned with code 1, though mentioned variables were set in yml.
I tried to start with just centos/mongodb image, install apache, php and whatnot, commit it, and work on my own image, but without kernel it's hard to properly install and run apache within docker container.
So i tried once more, found promising project here: https://github.com/akhomy/docker-compose-lamp
but can't attach to the container, can't run localhost with default settings, though apparently composing stage goes ok.
Has anyone of You, by chance, working set of docker files / docker-compose?
Or some helpful hint? Really, looks like a straightforward task, take two images from docker hub, make docker-compose.yml, run docker-compose up, case closed. I can't wrap my head around this :|
Docker approach is not to put all services in one container but to have a single container for a single service. All Docker tools are aligned to this.
For your LAMP stack to start, you just have to download docker-compose, create docker-compose.yml file with 3 services defined and run docker-compose up
Docker compose is an orchestrating tool for containers, suited for single machine.
You need to have at least small tour over this tool, just for an example I provide sample config file:
docker-compose.yml
version: '3'
services:
apache:
image: bitnami/apache:latest
.. here goes apache config ...
db:
image: mongo
.. here goes apache config ...
php:
image: php
.. here goes php config ...
After you start this with docker-compose up you will get network created automatically for you and all services will join it. They will see each other under their names (lets say to connect to database from php you will use db as host name).
To connect to this stuff from host PC, you will need to expose ports explicitly.
I am attempting to get a Docker container running PHP7, with a specific volume location and specific port 55211:80
When I add the following code to my docker-compose.yml file and compose up, the process is successful.
phpsandbox:
container_name: php_sandbox
restart: always
image: php:7
ports:
- "55211:80"
volumes:
- ./phpsandbox:/var/www/html/
I can see that my volume directory exists with my index.php inside...But if I then go to localhost:55211 in my browser, the browser says...
This page isn’t working localhost didn’t send any data.
What am I doing wrong in this part of my docker-compose.yml file?
UPDATE
From powershell, if I type in docker ps -a to see all running containers, php_sandbox is continosuly restarting, so I KNOW that something is wrong with this piece of code in my docker-compose.yml file, but don't know what...
Thanks!
The php:7 image only includes command line php tools. The image does not include a web server, so there is nothing on port 80 to respond to requests.
Try the php:7-apache image which comes with a preconfigured Apache httpd 2 web server that should work with your compose config.
I'm wondering if I've stumbled on a bug or that there's something not properly documented about variable substitution on Windows in combination with Docker Machine and Compose (installed version of docker is 1.11.1).
If I run the "docker-compose up" command for a yml file that looks like this:
volumes:
- ${FOOBAR}/build/:/usr/share/nginx/html/
And this variable doesn't exist docker compose will correctly complain about it:
The foobar variable is not set. Defaulting to a blank string.
However, when I change it to an existing environment variable:
volumes:
- ${PROJECT_DIR}/build/:/usr/share/nginx/html/
It will then not properly start the container and displays the following error (trying to access the nginx container will give you a host is unreachable message):
ERROR: for nginx rpc error: code = 2 desc = "oci runtime error: could not synchronise with container process: not a directory"
If I run the echo command in the Docker Quickstart Terminal it will output the correct path that I've set in the environment variable. If I replace the ${PROJECT_DIR} with the environment variable value the container runs correctly.
I get the same type of error message if I try to use the environment variable for the official php image instead of the official nginx image. In both cases the docker compose file works if I substitute ${PROJECT_DIR} text with the content of the environment variable.
So is this a bug or am I missing something?
After some mucking about I've managed to get the containers to start correctly without error messages if I use the following (contains the full path to the local files):
volumes:
- ${PROJECT_DIR}:/usr/share/nginx/html/
The nginx container is then up and running though it cannot find the files then anymore. If I replace the variable with the path it contains it then can find the files again.
Above behaviour isn't consistent. When I added a second environment variable for substitution it gave the oci runtime error. Kept giving it when I removed that second variable and only started working again when I also removed the first variable. After that it suddenly accepted ${PROJECT_DIR}/build/ but still without finding files.
Starting a bash session to the nginx container shows that the mount point for the volume contains no files.
I'm really at a loss here what docker is doing and what it expects from me. Especially as I have no idea to what it is expanding the variables in the compose file.
In the end the conclusion is that variable substitution is too quirky on Windows with Docker Machine to be useful. However, there is an alternative to variable substitution.
If you need a docker environment that does the following:
Can deploy on different computers that don't run the same OS
Doesn't care if the host uses Docker natively or via Virtual Box (this can require path changes)
Then your best bet is to use extending.
First you create the docker-compose.yml file that contains the images you'll need. For example an php image with MySQL:
php:
image: 5.5-apache
links:
- php_db:mysql
- maildev:maildev
ports:
- 8080:80
php_db:
image: mariadb
ports:
- 3306:3306
environment:
MYSQL_ROOT_PASSWORD: examplepass
You might notice that there aren't any volumes defined in this docker-compose file. That is something we're going to define in a file called docker-compose.override.yml:
php:
volumes:
- /workspaces/Eclipse/project/:/var/www/html/
When you have both files in one directory docker-compose does something interesting. It combines them into one adding/overwriting settings in the docker-compose.yml with those present in docker-compose.override.yml.
Then when running the command docker-compose up it will result in a docker run that is configured for the machine you're working on.
You can get similar behaviour with custom files names if you change a few things in your docker-compose command:
docker-compose -f docker-compose.yml -f docker-compose.conf.yml up
The detail is that docker-compose can accept multiple compose files and it will combine them into one. This happens from left to right.
Both methods allows you to create a basic compose file that configures the containers you need. You then can override/add the settings you need for the specific computer you're running docker on.
The page Overview of docker-compose CLI has more details on how these commands work.
I have been trying to user docker-compose to spin up a postgres container container, with a single, persisted named volume.
The goal is to have different postgres containers share the same persisted data (not concurrently!) - one container dies or is killed, another takes it place without losing previously persisted data.
As I understand "named volumes" are supposed to replace "Data Volume Containers".
However, so far either one of two things happen:
The postgres container fails to start up, with error message "ERROR: Container command not found or does not exist."
I achieve persistance for only that specific container. If it is stopped and removed and another container started, we start with a blank slate.
SO, as far as I understand, the postgres image does create it's own volume, which is of course bound to that specific container. Which would be fine, if I could just get THAT volume aliased or linked or something with the named volume.
Current incarnation of docker-compose.yml:
version: '2'
services:
db:
image: postgres
restart: allways
volumes:
- myappdb:/var/lib/postgresql/data/
environment:
- POSTGRES_PASSWORD=mysecretpasswordPleaseChangeME
volumes:
myappdb:
driver: local
Am I doing something stupidly wrong, or attempting something that is simply not supported?
Docker version 1.10.3, build 20f81dd
docker-compose version 1.6.0,
build d99cad6
Ok, after a lot of trial and error, things are now working as they should (meaning I am able to run docker-compose down and then docker-compose up and my data is in the state where it was left with the down command).
In general, a few things:
Don't use the PGDATA environment option with the official postgres image
If using spring boot (like I was), and docker compose (as I was) and passing environment options to a service linked to your database container, do not wrap a profile name in double quotes. It is passed as-is to the Spring as-is, resulting in a non-existing profile to be used as the active profile.
I had some subtle and strange things incorrectly configured initially, but I suspect the killer was point 2 above - it caused my app,when running in a container, to use in-mem H2 database instead of the linked container database. So everything functioned (almost) perfectly - until container shutdown. And, when running from IDE, against container DB (with ports exposed to host), all worked perfectly (including persistence), since the active profile parameter was correctly set in the IDE launcher (NO quotes!).
Live and learn I guess (but I do feel a LOT of egg on my face).
You need to tell Compose that it should manage creation of the Volume, otherwise it assumes it should already exist on the host.
volumes:
myappdb:
external: false
Docs: https://docs.docker.com/compose/compose-file/#external
Maybe I'm missing this when reading the docs, but is there a way to overwrite files on the container's file system when issuing a docker run command?
Something akin to the Dockerfile COPY command? The key desire here is to be able to take a particular Docker image, and spin several of the same image up, but with different configuration files. (I'd prefer to do this with environment variables, but the application that I'm Dockerizing is not partial to that.)
You have a few options. Using something like docker-compose, you could automatically build a unique image for each container using your base image as a template. For example, if you had a docker-compose.yml that look liked:
container0:
build: container0
container1:
build: container1
And then inside container0/Dockerfile you had:
FROM larsks/thttpd
COPY index.html /index.html
And inside container0/index.html you had whatever content you
wanted, then running docker-compose build would generate unique
images for each entry (and running docker-compose up would start
everything up).
I've put together an example of the above
here.
Using just the Docker command line, you can use host volume mounts,
which allow you to mount files into a container as well as
directories. Using my thttpd as an example again, you could use the
following -v argument to override /index.html in the container
with the content of your choice:
docker run -v index.html:/index.html larsks/thttpd
And you could accomplish the same thing with docker-compose via the
volume entry:
container0:
image: larsks/thttpd
volumes:
- ./container0/index.html:/index.html
container1:
image: larsks/thttpd
volumes:
- ./container1/index.html:/index.html
I would suggest that using the build mechanism makes more sense if you are trying to override many files, while using volumes is fine for one or two files.
A key difference between the two mechanisms is that when building images, each container will have a copy of the files, while using volume mounts, changes made to the file within the image will be reflected on the host filesystem.