502 Bad Gateway - nginx/1.14.0 (Ubuntu): Unable to find image locally + Error response from daemon

Recently I moved my Dell Server from one location to another. Its Main OS/VM Manager is Proxmox VE 5.3. I got an Nginx VM that is Reverse Proxying several other VMs, one of which is a Discourse VM.

After configuring my new Router, I got several of my VMs to connect to the Internet (not even needing to renew the SSL certificates). However, with Discourse, I am receiving 502 Bad Gateway - nginx/1.14.0 (Ubuntu) when trying to access Discourse in a Browser.

I have received this error before, but usually one of the below methods fixes it:

Restarting Discourse VM

Still 502 Bad Gateway - nginx/1.14.0 (Ubuntu) in a Browser.

Clearing Browser Cookies and Trying Different Browsers

Just in case it’s something on my end … nope. Same 502 Bad Gateway - nginx/1.14.0 (Ubuntu) in various Browsers.

Discourse Cleanup and Checking Diskspace

Initially when cleaning up, it removed about 4 GB of data. I was very surprised. Maybe that is what caused the problem in the first place? Anyways, now when I try to cleanup Discourse:

> root@forum:/var/discourse# ./launcher cleanup
> WARNING! This will remove all stopped containers.
> Are you sure you want to continue? [y/N] y
> Total reclaimed space: 0B
> WARNING! This will remove all images without at least one container associated to them.
> Are you sure you want to continue? [y/N] y
> Total reclaimed space: 0B

I also want to reiterate that I am not out of disk space:

Git Pull

It’s up to date.

> root@forum:/var/discourse# git pull
> Already up to date.

Restarting Discourse

This is where I discovered two errors that I’m receiving:

> root@forum:/var/discourse# ./launcher restart app
> 
> WARNING: We are about to start downloading the Discourse base image
> This process may take anywhere between a few minutes to an hour, depending on your network speed
> 
> Please be patient
> 
> Unable to find image 'discourse/base:2.0.20191013-2320' locally
> /usr/bin/docker: Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers).
> See '/usr/bin/docker run --help'.
> Your Docker installation is not working correctly
> 
> See: `https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam`

Checked out the suggested link. It recommends a Git Pull and to Rebuild Discourse (which you’ll see what I get later below). It also suggests running a Docker “Hello World” command. It works (although seems to have some problems?):

> root@forum:/var/discourse# docker run -it --rm hello-world
> Unable to find image 'hello-world:latest' locally
> latest: Pulling from library/hello-world
> 1b930d010525: Pull complete
> Digest: sha256:c3b4ada4687bbaa170745b3e4dd8ac3f194ca95b2d0518b417fb47e5879d9b5f
> Status: Downloaded newer image for hello-world:latest
> 
> Hello from Docker!
> This message shows that your installation appears to be working correctly.
> 
> To generate this message, Docker took the following steps:
>  1. The Docker client contacted the Docker daemon.
>  2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
>     (amd64)
>  3. The Docker daemon created a new container from that image which runs the
>     executable that produces the output you are currently reading.
>  4. The Docker daemon streamed that output to the Docker client, which sent it
>     to your terminal.
> 
> To try something more ambitious, you can run an Ubuntu container with:
>  $ docker run -it ubuntu bash
> 
> Share images, automate workflows, and more with a free Docker ID:
>  https://hub.docker.com/
> 
> For more examples and ideas, visit:
>  https://docs.docker.com/get-started/
> 
> failed to resize tty, using default size

Well, next I tried the Ubuntu Bash … and error:

> root@forum:/var/discourse# docker run -it ubuntu bash
> Unable to find image 'ubuntu:latest' locally
> docker: Error response from daemon: Get https://registry-1.docker.io/v2/library/ubuntu/manifests/latest: Get https://auth.docker.io/token?scope=repository%3Alibrary%2Fubuntu%3Apull&service=registry.docker.io: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers).
> See 'docker run --help'.

Time to move on to some other methods I know:

Stopping and Starting Discourse

Receiving the same thing as with the Restart:

> root@forum:/var/discourse# ./launcher stop app
> 
> WARNING: We are about to start downloading the Discourse base image
> This process may take anywhere between a few minutes to an hour, depending on your network speed
> 
> Please be patient
> 
> Unable to find image 'discourse/base:2.0.20191013-2320' locally
> /usr/bin/docker: Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers).
> See '/usr/bin/docker run --help'.
> Your Docker installation is not working correctly
> 
> See: `https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam`
> 
> root@forum:/var/discourse# ./launcher start app
> 
> WARNING: We are about to start downloading the Discourse base image
> This process may take anywhere between a few minutes to an hour, depending on your network speed
> 
> Please be patient
> 
> Unable to find image 'discourse/base:2.0.20191013-2320' locally
> /usr/bin/docker: Error response from daemon: Get https://registry-1.docker.io/v2/discourse/base/manifests/2.0.20191013-2320: Get https://auth.docker.io/token?scope=repository%3Adiscourse%2Fbase%3Apull&service=registry.docker.io: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers).
> See '/usr/bin/docker run --help'.
> Your Docker installation is not working correctly
> 
> See: `https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam`

Rebuild Discourse

And getting the same two errors again.

> root@forum:/var/discourse# ./launcher rebuild app
> 
> WARNING: We are about to start downloading the Discourse base image
> This process may take anywhere between a few minutes to an hour, depending on your network speed
> 
> Please be patient
> 
> Unable to find image 'discourse/base:2.0.20191013-2320' locally
> /usr/bin/docker: Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers).
> See '/usr/bin/docker run --help'.
> Your Docker installation is not working correctly
> 
> See: https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam

Restoring from a Previous Backup

I have a snapshot from a time before I moved the Server and did the Cleanup (which as mentioned, cleaned up about 4 GB of files). I tried all of the above again … and same thing (minus the Cleanup), as well as the 502 Bad Gateway - nginx/1.14.0 (Ubuntu) in a Browser. So perhaps this has nothing to do with the Cleanup?

In all my time with Discourse, I’ve never run into either of these errors. Any suggestions on what I can do to resolve these errors and get Discourse running in a browser?

Your server can’t connect to the docker hub in order to download large images, only the small hello world succeeded.

2 Likes

So how do I remedy this? I don’t have much experience using Docker, so I don’t know where to start.

The only Docker stuff I know is the commands the Discourse Install included (along with modifications of course, since Discourse is installed on a VM on a Server of mine as opposed to a Third Party Cloud).

Which docker version are you running (docker info)?

Can you check your network stack for problems stablishing connections to https://registry-1.docker.io/v2/ ?

Here is my Docker info:

root@forum:/var/discourse# docker info
Containers: 1
Running: 1
Paused: 0
Stopped: 0
Images: 3
Server Version: 18.09.5
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: bb71b10fd8f58240ca47fbb579b9d1028eea7c84
runc version: 2b18fe1d885ee5083ef9f0838fee39b62d653e30
init version: fec3683
Security Options:
apparmor
seccomp
Profile: default
Kernel Version: 4.15.0-69-generic
Operating System: Ubuntu 18.04.2 LTS
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 6.805GiB
Name: forum
ID: 2RRX:ZQIT:R5AK:WNPR:VJ6Z:2EBY:PFOL:W5RD:GL3X:RUQM:YLJ4:2L2X
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine

WARNING: No swap limit support

As for your question:

How do I do this?

@Falco So I’ve been trying to Troubleshoot this problem further, and I’m even more confused now. Good News and Bad News:

Good News

After performing several Discourse Rebuilds (./launcher rebuild app), I no longer receive the Unable to find image or Error response from daemon errors! When I Start/Restart Discourse, I see no errors:

> root@forum:/var/discourse# ./launcher start app
> 
> .+ /usr/bin/docker run --shm-size=512m -d --restart=always -e LANG=en_US.UTF-8 -e RAILS_ENV=production -e UNICORN_WORKERS=4 -e UNICORN_SIDEKIQS=1 -e RUBY_GLOBAL_METHOD_CACHE_SIZE=131072 -e RUBY_GC_HEAP_GROWTH_MAX_SLOTS=40000 -e RUBY_GC_HEAP_INIT_SLOTS=400000 -e RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR=1.5 -e DISCOURSE_DB_SOCKET=/var/run/postgresql -e DISCOURSE_DB_HOST= -e DISCOURSE_DB_PORT= -e DISCOURSE_HOSTNAME=discourse.example.com -e DISCOURSE_DEVELOPER_EMAILS=admin@example.com,postmaster@example.com -e DISCOURSE_SMTP_ADDRESS=smtp.sparkpostmail.com -e DISCOURSE_SMTP_PORT=587 -e DISCOURSE_SMTP_USER_NAME=SMTP_Injection -e DISCOURSE_SMTP_PASSWORD=<HIDING-FOR-PRICACY> -e LETSENCRYPT_ACCOUNT_EMAIL=admin@example.com -h forum-app -e DOCKER_HOST_IP=100.17.0.1 --name app -t -p 8080:80 -p 8443:443 -p 2222:22 -v /var/discourse/shared/standalone:/shared -v /var/discourse/shared/standalone/log/var-log:/var/log --mac-address 02:96:f3:e6:e7:14 local_discourse/app /sbin/boot
> cebe89493bc79dab2c1716599629adfe3dc571c8659367e6ffa0d39b0e6d47af
> root@forum:/var/discourse# ./launcher restart app
> .+ /usr/bin/docker stop -t 10 app
> app
> 
> starting up existing container
> .+ /usr/bin/docker start app
> app

Docker is also running:
> root@forum:/var/discourse# systemctl status docker.service
> ● docker.service - Docker Application Container Engine
>    Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
>    Active: active (running) since Thu 2019-11-14 03:00:54 UTC; 17h ago
>      Docs: https://docs.docker.com
>  Main PID: 18721 (dockerd)
>     Tasks: 31
>    CGroup: /system.slice/docker.service
>            ├─ 1375 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 8443 -container-ip 172.17.0.2 -container-port 443
>            ├─ 1387 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 8080 -container-ip 172.17.0.2 -container-port 80
>            ├─ 1399 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 2222 -container-ip 172.17.0.2 -container-port 22
>            └─18721 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
> 
> Nov 14 20:13:26 forum dockerd[18721]: time="2019-11-14T20:13:26.430856242Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:28 forum dockerd[18721]: time="2019-11-14T20:13:28.597999379Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:30 forum dockerd[18721]: time="2019-11-14T20:13:30.862158413Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:32 forum dockerd[18721]: time="2019-11-14T20:13:32.978285148Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:35 forum dockerd[18721]: time="2019-11-14T20:13:35.105130149Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:37 forum dockerd[18721]: time="2019-11-14T20:13:37.151466214Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:13:39 forum dockerd[18721]: time="2019-11-14T20:13:39.024948159Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:14:05 forum dockerd[18721]: time="2019-11-14T20:14:05.179759938Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
> Nov 14 20:14:16 forum dockerd[18721]: time="2019-11-14T20:14:16.078334393Z" level=info msg="Container cebe89493bc79dab2c1716599629adfe3dc571c8659367e6ffa0d39b0e6d47af failed to exit within
> Nov 14 20:14:16 forum dockerd[18721]: time="2019-11-14T20:14:16.281731176Z" level=info msg="ignoring event" module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"

Bad News

Still receiving the 502 Bad Gateway - nginx/1.14.0 (Ubuntu) error when I try to open the site in various Browser. I’ve cleared their caches and tried multiple Browsers just in case. No go.

One thing I have noticed is if I try a Discourse Cleanup, it wipes quite a few Containers:

> root@forum:/var/discourse# ./launcher cleanup
> WARNING! This will remove all stopped containers.
> Are you sure you want to continue? [y/N] y
> Total reclaimed space: 0B
> WARNING! This will remove all images without at least one container associated to them.
> Are you sure you want to continue? [y/N] y
> Deleted Images:
> untagged: hello-world:latest
> untagged: hello-world@sha256:c3b4ada4687bbaa170745b3e4dd8ac3f194ca95b2d0518b417fb47e5879d9b5f
> deleted: sha256:fce289e99eb9bca977dae136fbe2a82b6b7d4c372474c9235adc1741675f587e
> deleted: sha256:af0b15c8625bb1938f1d7b17081031f649fd14e6b233688eea3c5483994a66a3
> untagged: discourse/base:2.0.20191013-2320
> untagged: discourse/base@sha256:77e010342aa5111c8c3b81d80de7d4bdb229793d595bbe373992cdb8f86ef41f
> deleted: sha256:53b44681b65ee5e9a9cadc6bd34c6aa6f6bcbbbe6270e61669c50bcd655c6898
> deleted: sha256:939a3ac6d5627270ae02a9f9ea05c580589cec0afa019b7f296fdd43157dd3a0
> 
> Total reclaimed space: 452.2MB

Now anytime I try to start/restart … the errors are back! I’ve rolled back to when the Unable to find image or Error response from daemon error messages stopped showing up. Clearly Containers were rebuilt, and clearing the image containers causes issues.

If your docker is broken (aka docker run ubuntu fails) Discourse most certainly won’t work.

To get Docker specific Docker support you may try posting https://forums.docker.com/

1 Like

@Falco Yeah, I’m getting the Unable to find image locally and Error response from daemon errors as I was getting before when I run that command.

So as per your suggestion, I’ve started a topic over in the Docker forums. No response yet unfortunately.

1 Like

Please stop posting code as blockquotes. Use code blocks. Otherwise you create a lot of work for me, fixing all your posts.

@codinghorror my apologies, I keep forgetting about Code Blocks. I won’t use Block Quotes anymore.

1 Like

So some more news:

Good News

I’m not receiving the /usr/bin/docker: Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers). anymore!

docker run ubuntu no longer reports an error. @Falco is there supposed to be any output I should be seeing?

root@forum:/var/discourse# docker run ubuntu
root@forum:/var/discourse#

So what have I done that resolves the error? I replaced the nameserver (DNS) used on this VM by the Google Public DNS service:
echo "nameserver 8.8.8.8">/etc/resolv.conf

I have to run the above command every time after the VM is restarted though (so it seems to just be temporary), or I will get the two errors when I try to run any ./launcher commands. Afterwards though, only one of the errors (Unable to find image 'discourse/base:2.0.20191013-2320' locally) comes up, but the command looks to resolve:

root@forum:/var/discourse# ./launcher start app

WARNING: We are about to start downloading the Discourse base image
This process may take anywhere between a few minutes to an hour, depending on your network speed

Please be patient

Unable to find image 'discourse/base:2.0.20191013-2320' locally
2.0.20191013-2320: Pulling from discourse/base
Digest: sha256:77e010342aa5111c8c3b81d80de7d4bdb229793d595bbe373992cdb8f86ef41f
Status: Downloaded newer image for discourse/base:2.0.20191013-2320

starting up existing container
+ /usr/bin/docker start app
app

I look to also be able to do a ./launcher rebuild app without errors. Here is the last thing the output of the command shows (hiding URLs and MAC Address):

+ /usr/bin/docker run --shm-size=512m -d --restart=always -e LANG=en_US.UTF-8 -e RAILS_ENV=production -e UNICORN_WORKERS=4 -e UNICORN_SIDEKIQS=1 -e RUBY_GLOBAL_METHOD_CACHE_SIZE=131072 -e RUBY_GC_HEAP_GROWTH_MAX_SLOTS=40000 -e RUBY_GC_HEAP_INIT_SLOTS=400000 -e RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR=1.5 -e DISCOURSE_DB_SOCKET=/var/run/postgresql -e DISCOURSE_DB_HOST= -e DISCOURSE_DB_PORT= -e DISCOURSE_HOSTNAME=discourse.domain.com -e DISCOURSE_DEVELOPER_EMAILS=admin@domain.com,postmaster@domain.com -e DISCOURSE_SMTP_ADDRESS=smtp.sparkpostmail.com -e DISCOURSE_SMTP_PORT=587 -e DISCOURSE_SMTP_USER_NAME=SMTP_Injection -e DISCOURSE_SMTP_PASSWORD=0d431cd177ce3d35833aa823d498eb57c7c4e99c -e LETSENCRYPT_ACCOUNT_EMAIL=admin@domain.com -h forum-app -e DOCKER_HOST_IP=172.17.0.1 --name app -t -p 8080:80 -p 8443:443 -p 2222:22 -v /var/discourse/shared/standalone:/shared -v /var/discourse/shared/standalone/log/var-log:/var/log --mac-address 00:00:00:00:00:01 local_discourse/app /sbin/boot
abb788d4a6fd301d88f129189a07a19c4a6bfc8554d43c555d3e3cd126374736

Bad News

I am still getting the 502 Bad Gateway - nginx/1.14.0 (Ubuntu) error when I try going to the page.

What else could be the issue? Any suggestions?

Please don’t tag people directly. The support here is free and best-effort, people will check in when they’re able.

Your problem looks to be related to your networking, this isn’t a discourse issue.

My apologies. I have removed the tags of both users from my last post.

1 Like

I resolved my issue! My Discourse Forum shows up now in a Browser!

Well, to be more specific, Francis Day over on the Nginx Forums resolved my issue! It was indeed Nginx all along. Here is what I did:

  1. Logged into my Nginx VM.
  2. VIMed Discourse CONF file: vim /etc/nginx/sites-available/discourse.conf
  3. Here is what my Discourse CONF file looked like (obviously not using the Domain Name I would normally use, and where 192.168.0.101 = Nginx VM and 192.168.0.104 = Discourse VM).
  4. I only made one change: I changed proxy_pass http://discourse.domainame.com:8080/; to proxy_pass 192.168.0.104:8080/;. So proxy_pass is set to the Discourse VM’s Local IP instead of the Hostname.
  5. Save the CONF file, and then Reloaded (systemctl reload nginx.service) and Restarted (systemctl restart nginx.service) Nginx.
  6. Viola! I refresh the Discourse URL, and it comes up! Didn’t even need to Restart/Rebuild Discourse!

I hope someone finds what I’ve written here useful, as reverse proxying Discourse through Nginx can be really tricky.