I'm my wits end with this, I've combed every single google result and nothing helps.
I'm completely unable to get docker containers to access the internet. IP forwarding is enabled (net.ipv4.ip_forward = 1), ufw is turned off, I've tried adding the -dns 8.8.8.8 -dns 8.8.4.4 flags. Every possible solution I've ever found on google fails.
Anyone have any idea how to help?
Attempting to reset everything, as recommend here causes the entire thing to break by telling me that docker -d isn't running even though it is.
I was facing the same problem. So, to solve that issue I've started the container using the argument --net=host, it worked perfectly for me.
Here goes the full statement
sudo docker start --net=host -it --name ex_ngninx ubuntu
Resolved. I followed these instructions: commented out dns=dnsmasq line in NetworkManager.conf
Related
I set up a wp-env environment a while ago to tinker with a website I was working on..
Today I went to work on it some more and when I ran wp-env start I got the error in the image.
I have tried using the default "localhost" instead of 127.0.0.1 as well as including the port like 127.0.0.1:8888 to no avail. I have run all docker clean and destroy commands and restarted and updated the mysql server and Docker itself. What are some next steps I can take? Thanks!
I'm doing an internship focused on Docker and I have to load-balance an application which have a client, a server and a database. I use Nginx as a load-balancer and my goal is to dynamically scale the number of server containers according their CPU usage. For instance if the CPU usage is over 60% I want to add a new container on the fly without restarting Nginx to divide the CPU usage.
I have to modify the nginx.conf file to add a new container but I have to restart the Nginx container to apply the changes, which is very slow.
So my question is : is there a (free) way to do it dynamically ?
Tell me if you want further information and forgive my poor english.
Thanks.
EDIT : I did as #Konstantin Azizov told me :
docker cp ./new.conf $(docker ps -f "name=dockerizedrubis_nginx" -q ):/etc/nginx/nginx.conf
docker exec $(docker ps -f "name=dockerizedrubis_nginx" -q) bash -c 'kill -HUP $(cat /run/nginx.pid)'
docker exec $(docker ps -f "name=dockerizedrubis_nginx" -q) bash -c '/etc/init.d/nginx reload'
The configuration file is well pasted in the container supporting Nginx, I send the HUP signal to reconfigure the Nginx process et then I reload to apply my changes. There are no errors and the reload on-the-fly works fine but my new nodes are not taken into account by Nginx, the requests are still only directed to the first node created ...
EDIT 2 : I found the origin of the problem. It seems like in order to update the /etc/hosts of a container after a 'docker-compose scale', this container needs to be stopped, removed and restarted. In my case, I really don't want to stop the container supporting Nginx.
Question : Anyone has an idea of how to update /etc/hosts of a container after a re-scale without having to restart the container (beside a dirty script) ?
Thanks.
I used the nginx-proxy image from Json Wilder for a while to load balance between containers, and it works for more than one scalable service. It monitors the docker daemon and if an event happens it rebuilds the nginx config file adding the new container instances when you are scaling out or removing it if you are scaling in.
Since Docker 1.10 (not sure if this is the correct version) there is a internal DNS embedded into Docker daemon, so since then I am using the round robin feature from it. Now I am using the oficial nginx image to proxy pass the requests to the a domain that I define as alias into network options. I do not know if I was clear due to my poor english but I believe my Github example may help.
Unfortunately there is no easy(free) way to change configuration without restarting, the only way to achieve zero-downtime scaling it's graceful restart, when you restarting Nginx gracefully it will spawn new instance with new configuration wait until it boots up and then kill old instance with the previous configuration.
See official guide.
I've currently got a cluster of servers running Centos 7 and Docker, and I want to use Keepalived to allocate a floating IP between them. I've configured Keepalived to run a check command on each node which just does curl --silent --fail localhost:80 to ensure a HTTP server is listening.
The web app is running using a Docker container bound to port 80 and --net=host on Docker 1.10.3. Firewalld is also completely disabled.
The problem I'm having is that the curl never succeeds. If I change the check command to echo '' or anything else which exits 0 (without any network interaction) it works fine, but for some reason the curl doesn't work. When I run it from a normal bash terminal it is fine, and echo $? prints a 0.
I'm not even sure how to debug this as Keepalived doesn't provide any documentation on the matter and doesn't seem to log anything in relation to errors coming from the vrrp script.
Any help or suggestions would be greatly appreciated.
Turns out I was using an ancient version of Keepalived. Compiling the latest version from source fixed the issue (rather than using the binary from Centos repos)
I am trying to access etcd from within a running Docker container. When I run
curl http://172.17.42.1:4001/v2/keys
I get
curl: (7) Failed to connect to 172.17.42.1 port 4001: Connection refused
I have four other hosts where this works fine, but every container on this machine has this problem. I'm really at a loss as to what's going on, and I don't know how to debug it.
My etcd environment variables are
ETCD_ADVERTISE_CLIENT_URLS=http://10.242.10.2:2379
ETCD_DISCOVERY=https://discovery.etcd.io/<token_removed>
ETCD_INITIAL_ADVERTISE_PEER_URLS=http://10.242.10.2:2380
ETCD_LISTEN_CLIENT_URLS=http://10.242.10.2:2379,http://127.0.0.1:2379,http://0.0.0.0:4001
ETCD_LISTEN_PEER_URLS=http://10.242.10.2:2380
I can also access etcd from the host with
curl http://localhost:4001/v2/keys
So there seems to be some error when routing from the container out to the host. But I can't figure out what it is. Can anyone point me in the right direction?
I observed I had to use the --advertise-client-urls and --listen-client-urls. Like so:
./etcd --advertise-client-urls 'http://0.0.0.0:2379,http://0.0.0.0:4001' --listen-client-urls 'http://0.0.0.0:2379,http://0.0.0.0:4001'
Then I was able to successfully do
curl -L http://hostname:2379/version
from any machine that could reach that server and it worked.
It turns out etcd was only listening on localhost:4001 on that machine, which is why I couldn't access it from within a container. This is despite me configuring one of the listen client urls to 0.0.0.0:4001.
It turns out that I had run sudo systemctl enable etcd2, which caused it to run before the cloud-config service ran. As such, etcd started with default configuration instead of the one that I had specified in my cloud config. Running sudo systemctl disable etcd2 fixed the issue.
I have a small nginx based test application that I want to run inside a docker container. So I followed the example given here docker installation
So I have a foder name restartTest and it contains an index.html file that has this single line in it that says Docker Test 1. I mount this up as my volume during runtime for docker container. So the commmand I use is
docker run -dP -v /Users/Sachin/restartTest/:/usr/share/nginx/html --name engine2 nginx
And it runs fine. I use curl to verify that the volume has mounted properly and the application is running as desired. Now what I do is that I change the content of the index.html file (from my localhost) to Docker test 2 and then I restart the container. I execute the following command to verify that the content has indeed changed inside the docker container
docker exec engine2 cat /usr/share/nginx/html/index.html
And as expected, the file reads Docker Test 2. However, when I use the curl command to see if the webpage also reflects the change I see that I still get Docker Test 1 as the response. The index.html reflects the change however when I run the curl command or if I access the app from the browser, I still get the same result. I have tried the following but to no avail.
Restart the service
Stop and start the container
Stop and start the boot2docker VM and docker daemon.
I have no clue as to why this is happening.
So I found this known bug with VirtualBox VM that is used for running Docker on Mac.
When we have shared content between our host machine and the VirtualBox, then only we face this bug. There is a optimisation as far as web servers like nginx, apache (and apparently vertx) are concerned. Whenever we request a static file from the server, it uses sendfile to provide us with the file. The bug is that in case of VirtualBox (in the scenario described above) we always get the first version of the file no matter what we try. The workaround for this in case of nginx and apache is to turn sendfile off . However, there is a hack that we use as far as vertx is concerned.
rename the file say login.html to login.html.moved (anything)
curl :/….../login.html (we won’t get anything)
rename the file back to its original name login.html.moved to login.html
Hard refresh the page (Command + Shift + R).
For further reading about this bug consult the following
Link1
Link2
Link3
Link4
I assume it is a caching problem. Did you try to set expires -1 in your index.html location configuration to disable server side caching for static files?