ignite-cntr

README

ignite-cntr

Tool to build ignite VM image with a conatiner-runtime and preloaded images. It also helps to run the container application inside the VM.

By default, containerd is used as the container-runtime inside the VM. Support for other container-runtime may be added in the future.

Building VM Image

Build a VM image with preloaded container images:

$ ignite-cntr image vm darkowlzz/ignite-etcd:test --image quay.io/coreos/etcd:v3.4.7
Started build container ignite-cntr-build-7198945983020451624
Starting containerd in the build container...
Creating containerd namespace: ignite...
Waiting for quay.io/coreos/etcd:v3.4.7 image pull to complete....

Created VM application image: darkowlzz/ignite-etcd:test (sha256:1eadb753b7ceabc68e3739bc1cdd32012ce18fb4c7fac94d86b316ee1e08d91a)

In the above example, the VM image is preloaded with an etcd container image. The created image is an ignite compatible image.

Similarly, more images can be passed using the --image flag:

$ ignite-cntr image vm darkowlzz/ignite-misc:test -i docker.io/library/busybox:latest -i docker.io/library/alpine:latest
Started build container ignite-cntr-build-2093644811210178439
Starting containerd in the build container...
Creating containerd namespace: ignite...
Waiting for docker.io/library/busybox:latest image pull to complete..
Waiting for docker.io/library/alpine:latest image pull to complete..

Created VM application image: darkowlzz/ignite-misc:test (sha256:8ce9bef42e5007ae5073d0c6d1b7b5c4eaa727104ddc8b425f7a9921bdcff83f)

By default, the VM image is based on darkowlzz/ignite-cntr-base:dev base image. This is based on weaveworks/ignite-ubuntu with containerd installed. To use a separate base image pass the image with --baseImage flag.

$ ignite-cntr image vm darkowlzz/ignite-etcd:test --image quay.io/coreos/etcd:v3.4.7 --baseImage foo/bar:baz
...

Building VM Base Image

VM base image can be built with the image base subcommand:

$ ignite-cntr image base
Building image...
Base image built: darkowlzz/ignite-cntr-base:dev

By default, darkowlzz/ignite-cntr-base:dev base image is created. It can be configured to build a different image by passing the name as an argument:

$ ignite-cntr image base foo/bar:baz
Building image...
Base image built: foo/bar:baz

The base image of this VM base image can be passed using the --baseImage flag.

Running the container application inside a VM

Before an application can be run, create an ignite VM that contains the application container image preloaded:

$ sudo ignite run darkowlzz/ignite-etcd:v0.0.1 --cpus 1 --memory 1GB --ssh --name=my-vm
INFO[0001] Created VM with ID "8e608e51e7cc0e92" and name "my-vm" 
INFO[0001] Networking is handled by "cni"               
INFO[0001] Started Firecracker VM "8e608e51e7cc0e92" in a container with ID "ignite-8e608e51e7cc0e92" 

$ sudo ignite ps
VM ID			IMAGE				KERNEL					SIZE	CPUS	MEMORY		CREATED	STATUS	IPS		PORTS	NAME
8e608e51e7cc0e92	darkowlzz/ignite-etcd:v0.0.1	weaveworks/ignite-kernel:4.19.47	4.0 GB	1	1024.0 MB	9s ago	Up 9s	10.61.0.54		my-vm

In the above, an ignite VM is created using an ignite-etcd VM image. To run etcd inside the VM, run:

$ sudo ignite-cntr run my-vm quay.io/coreos/etcd:v3.4.7 --env "ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379" --env "ETCD_ADVERTISE_CLIENT_URLS=http://10.61.0.52:2379" --net-host
CMD: ctr -n ignite container create quay.io/coreos/etcd:v3.4.7 container-app --env ETCD_ADVERTISE_CLIENT_URLS=http://10.61.0.54:2379 --env ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379 --net-host

NOTE: Like ignite, the run subcommand must be run with sudo.

In the above, etcd container is run with some environment variables and host netorking enabled. The command output shows the command executed to create a containerd container which is then run with a containerd task.

By default, a containerd namespace called ignite is created. The etcd containerd task can be checked by logging into the VM.

$ sudo ignite ssh my-vm
...
...
root@localhost:~# ctr -n ignite c ls
CONTAINER        IMAGE                         RUNTIME                  
container-app    quay.io/coreos/etcd:v3.4.7    io.containerd.runc.v2    

root@localhost:~# ctr -n ignite t ls
TASK             PID    STATUS    
container-app    969    RUNNING

For containers that require a command to be passed, use --cmd flag.

$ sudo ignite-cntr run my-vm docker.io/library/redis:5.0.8 --net-host --cmd redis-server
Creating container container-app-1944007321518467805...
CMD: /usr/bin/ctr -n ignite container create docker.io/library/redis:5.0.8 container-app-1944007321518467805 redis-server --net-host
[STDOUT]:

Running task container-app-1944007321518467805...
[STDOUT]:
1:C 07 Apr 2020 17:23:24.439 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 07 Apr 2020 17:23:24.439 # Redis version=5.0.8, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 07 Apr 2020 17:23:24.439 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
1:M 07 Apr 2020 17:23:24.440 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
1:M 07 Apr 2020 17:23:24.440 # Server can't set maximum open files to 10032 because of OS error: Operation not permitted.
1:M 07 Apr 2020 17:23:24.440 # Current maximum open files is 1024. maxclients has been reduced to 992 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
1:M 07 Apr 2020 17:23:24.440 * Running mode=standalone, port=6379.
1:M 07 Apr 2020 17:23:24.440 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:M 07 Apr 2020 17:23:24.440 # Server initialized
1:M 07 Apr 2020 17:23:24.440 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
1:M 07 Apr 2020 17:23:24.440 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
1:M 07 Apr 2020 17:23:24.440 * Ready to accept connections

Container Environment Variables File

Passing environment variables file is supported. In the above example, the etcd environment variables can be written into a file, say etcd.env:

ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379
ETCD_ADVERTISE_CLIENT_URLS=http://10.61.0.54:2379

This file can then be passed to the run subcommand as:

$ sudo ignite-cntr run my-vm quay.io/coreos/etcd:v3.4.7 --env-file etcd.env --net-host
CMD: ctr -n ignite container create quay.io/coreos/etcd:v3.4.7 container-app --env ETCD_ADVERTISE_CLIENT_URLS=http://10.61.0.54:2379 --env ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379 --net-host

It also supports merging flag based env vars and file based env vars.

Mounting Config File

Configuration file can be mounted into the container using the --mount-src and --mount-dest flags. For example, to run nginx with a config file:

$ sudo ignite-cntr run my-vm docker.io/library/nginx:1.17.10 --mount-src=default.conf --mount-dest=/etc/nginx/conf.d/default.conf --net-host

This will copy the config file into the VM and then mount the file into the application container at the specified destination.

Documentation

Overview

Copyright © 2020 NAME HERE <EMAIL ADDRESS>

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.