This is an ingress controller for Kubernetes — the open-source container deployment, scaling, and management system — on AWS. It runs inside a Kubernetes cluster to monitor changes to your ingress resources and orchestrate AWS Load Balancers accordingly.
This ingress controller uses the EC2 instance metadata of the worker node where it's currently running to find the additional details about the cluster provisioned by Kubernetes on top of AWS. This information is used to manage AWS resources for each ingress objects of the cluster.
- Uses CloudFormation to guarantee consistent state
- Automatic discovery of SSL certificates
- Automatic forwarding of requests to all Worker Nodes, even with auto scaling
- Automatic cleanup of unnecessary managed resources
- Support for both Application Load Balancers and Network Load Balancers.
- Support for internet-facing and internal load balancers
- Support for ignoring cluster-internal ingress, that only have
--cluster-local-domain=cluster.local
domains. - Support for denying traffic for internal domains.
- Support for multiple Auto Scaling Groups
- Support for instances that are not part of Auto Scaling Group
- Support for SSLPolicy, set default and per ingress
- Support for CloudWatch Alarm configuration
- Can be used in clusters created by Kops, see our deployment guide for Kops
- Support Multiple TLS Certificates per ALB (SNI).
- Support for AWS WAF and WAFv2
Version v0.12.0
changes Network Load Balancer type handling if Application Load Balancer type feature is requested. See Load Balancers types notes for details.
Version v0.11.0
changes the default apiVersion
used for fetching/updating
ingresses from extensions/v1beta1
to networking.k8s.io/v1beta1
. For this to
work the controller needs to have permissions to list
ingresses
and
update
, patch
ingresses/status
from the networking.k8s.io
apiGroup
.
See deployment example. To fallback to
the old behavior you can set the apiVersion via the --ingress-api-version
flag. Value must be extensions/v1beta1
or networking.k8s.io/v1beta1
(default).
Version v0.9.0
changes the internal flag parsing library to
kingpin this means flags are now defined with --
(two dashes)
instead of a single dash. You need to change all the flags like this:
-stack-termination-protection
-> --stack-termination-protection
before
running v0.9.0
of the controller.
Version v0.8.0
added certificate verification check to automatically ignore
self-signed and certificates from internal CAs. The IAM role used by the controller
now needs the acm:GetCertificate
permission. acm:DescribeCertificate
permission
is no longer needed and can be removed from the role.
Version v0.7.0
deletes the annotation
zalando.org/aws-load-balancer-ssl-cert-domain
, which we do not
consider as feature since we have SNI enabled ALBs.
Version v0.6.0
introduced support for Multiple TLS Certificates per ALB
(SNI). When upgrading your ALBs will automatically be aggregated to a single
ALB with multiple certificates configured.
It also adds support for attaching single EC2 instances and multiple
AutoScalingGroups to the ALBs therefore you must ensure you have the correct
instance filter defined before upgrading. The default filter is
tag:kubernetes.io/cluster/<cluster-id>=owned tag-key=k8s.io/role/node
see
How it works for more information on how to configure this.
Version v0.5.0
introduced support for both internet-facing
and internal
load balancers. For this change we had to change the naming of the
CloudFormation stacks created by the controller. To upgrade from v0.4.* to
v0.5.0 no changes are needed, but since the naming change of the stacks
migrating back down to a v0.4.* version will not be non-disruptive as it will
be unable to manage the stacks with the new naming scheme. Deleting the stacks
manually will allow for a working downgrade.
In versions before v0.4.0 we used AWS Tags that were set by CloudFormation automatically to find some AWS resources. This behavior has been changed to use custom non cloudformation tags.
In order to update to v0.4.0, you have to add the following tags to your AWs Loadbalancer SecurityGroup before updating:
kubernetes:application=kube-ingress-aws-controller
kubernetes.io/cluster/<cluster-id>=owned
Additionally you must ensure that the instance where the ingress-controller is
running has the clusterID tag kubernetes.io/cluster/<cluster-id>=owned
set
(was ClusterID=<cluster-id>
before v0.4.0).
Overview of configuration which can be set via Ingress annotations.
Name | Value | Default |
---|---|---|
alb.ingress.kubernetes.io/ip-address-type |
ipv4 | dualstack |
ipv4 |
zalando.org/aws-load-balancer-ssl-cert |
string |
N/A |
zalando.org/aws-load-balancer-scheme |
internal | internet-facing |
internet-facing |
zalando.org/aws-load-balancer-shared |
true | false |
true |
zalando.org/aws-load-balancer-security-group |
string |
N/A |
zalando.org/aws-load-balancer-ssl-policy |
string |
ELBSecurityPolicy-2016-08 |
zalando.org/aws-load-balancer-type |
nlb | alb |
alb |
zalando.org/aws-load-balancer-http2 |
true | false |
true |
zalando.org/aws-waf-web-acl-id |
string |
N/A |
kubernetes.io/ingress.class |
string |
N/A |
The defaults can also be configured globally via a flag on the controller.
The controller supports both Application Load Balancers and Network Load Balancers. Below is an overview of which features can be used with the individual Load Balancer types.
Feature | Application Load Balancer | Network Load Balancer |
---|---|---|
HTTPS | ✔️ | ✔️ |
HTTP | ✔️ | ✔️ --nlb-http-enabled |
HTTP -> HTTPS redirect | ✔️ --redirect-http-to-https |
✖️ |
Cross Zone Load Balancing | ✔️ (only option) | ✔️ --nlb-cross-zone |
Dualstack support | ✔️ --ip-addr-type=dualstack |
✖️ |
Idle Timeout | ✔️ --idle-connection-timeout |
✖️ |
Custom Security Group | ✔️ | ✖️ |
Web Application Firewall (WAF) | ✔️ | ✖️ |
HTTP/2 Support | ✅ | (not relevant) |
To facilitate default load balancer type switch from Application to Network when the default load balancer type is Network
(--load-balancer-type="network"
) and Custom Security Group (zalando.org/aws-load-balancer-security-group
) or
Web Application Firewall (zalando.org/aws-waf-web-acl-id
) annotation is present the controller configures Application Load Balancer.
If zalando.org/aws-load-balancer-type: nlb
annotation is also present then controller ignores the configuration and logs an error.
SecurityGroup auto detection needs the following AWS Tags on the SecurityGroup:
kubernetes.io/cluster/<cluster-id>=owned
kubernetes:application=<controller-id>
, controller-id defaults tokube-ingress-aws-controller
and can be set by flag--controller-id=<my-ctrl-id>
.
AutoScalingGroup auto detection needs the same AWS tags on the AutoScalingGroup as defined for the SecurityGroup.
In case you want to attach/detach single EC2 instances to the ALB
TargetGroup, you have to have the same <cluster-id>
set as on the
running kube-ingress-aws-controller. Normally this would be
kubernetes.io/cluster/<cluster-id>=owned
.
This controller is used in production since Q1 2017. It aims to be out-of-the-box useful for anyone running Kubernetes. Jump down to the Quickstart to try it out—and please let us know if you have trouble getting it running by filing an Issue. If you created your cluster with Kops, see our deployment guide for Kops
As of this writing, it's being used in production use cases at Zalando, and can be considered battle-tested in this setup. We're actively seeking devs/teams/companies to try it out and share feedback so we can make improvements.
We are also eager to bring new contributors on board. See our contributor guidelines to get started, or claim a "Help Wanted" item.
The maintainers of this project are building an infrastructure that runs Kubernetes on top of AWS at large scale (for nearly 200 delivery teams), and with automation. As such, we're creating our own tooling to support this new infrastructure. We couldn't find an existing ingress controller that operates like this one does, so we created one ourselves.
We're using this ingress controller with Skipper, an HTTP router that Zalando has used in production since Q4 2015 as part of its front-end microservices architecture. Skipper's also open source and has some outstanding features, that we documented here. Feel free to use it, or use another ingress of your choosing.
This controller continuously polls the API server to check for ingress resources. It runs an infinite loop. For each cycle it creates load balancers for new ingress resources, and deletes the load balancers for obsolete/removed ingress resources.
This is achieved using AWS CloudFormation. For more details check our CloudFormation Documentation
The controller will not manage the security groups required to allow access from the Internet to the load balancers. It assumes that their lifecycle is external to the controller itself.
During startup phase EC2 filters are constructed as follows:
- If
CUSTOM_FILTERS
environment variable is set, it is used to generate filters that are later used to fetch instances from EC2. - If
CUSTOM_FILTERS
environment variable is not set or could not be parsed, then default filters aretag:kubernetes.io/cluster/<cluster-id>=owned tag-key=k8s.io/role/node
where<cluster-id>
is determined from EC2 tags of instance on which Ingress Controller pod is started.
CUSTOM_FILTERS
is a list of filters separated by spaces. Each filter has a form of name=value
where name can be a tag:
or tag-key:
prefixed expression, as would be recognized by the EC2 API, and value is value of a filter, or a comma seperated list of values.
For example:
tag-key=test
will filter instances that have a tag namedtest
, ignoring the value.tag:foo=bar'
will filter instances that have a tag namedfoo
with the valuebar
tag:abc=def,ghi
will filter instances that have a tag namedabc
with the valuedef
ORghi
- Default filter
tag:kubernetes.io/cluster/<cluster-id>=owned tag-key=k8s.io/role/node
filters instances that has tagkubernetes.io/cluster/<cluster-id>
with valueowned
and have tag namedtag-key=k8s.io/role/node
.
Every poll cycle EC2 is queried with filters that were constructed during startup.
Each new discovered instance is scanned for Auto Scaling Group tag. Each Target
Group created by this Ingress controller is then added to each known Auto Scaling Group.
Each Auto Scaling Group information is fetched only once when first node of it is discovered for first time.
If instance does not belong to Auto Scaling Group (does not have aws:autoscaling:groupName
tag) it is stored in separate list of
Single Instances. On each cycle instances on this list are registered as targets in all Target Groups managed by this controller.
If call to get instances from EC2 did not return previously known Single Instance, it is deregistered from Target Group and removed from list of Single Instances.
Call to deregister instances is aggregated so that maximum 1 call to deregister is issued in poll cycle.
For Auto Scaling Groups, the controller will always try to build a list of
owned Auto Scaling Groups based on the tag:
kubernetes.io/cluster/<cluster-id>=owned
even if this tag is not specified in
the CUSTOM_FILTERS
configuration. Tracking the owned Auto Scaling Groups is
done to automatically deregister any ASGs which are no longer targeted by the
CUSTOM_FILTERS
.
On startup, the controller discovers the AWS resources required for the controller operations:
-
The Security Group
Lookup of the
kubernetes.io/cluster/<cluster-id>
tag of the Security Group matching the clusterID for the controller node andkubernetes:application
matching the valuekube-ingress-aws-controller
or as fallback for<v0.4.0
tagaws:cloudformation:logical-id
matching the valueIngressLoadBalancerSecurityGroup
(only clusters created by CF). -
The Subnets
Subnets are discovered based on the VPC of the instance where the controller is running. By default it will try to select all subnets of the VPC but will limit the subnets to one per Availability Zone. If there are many subnets within the VPC it's possible to tag the desired subnets with the tags
kubernetes.io/role/elb
(for internet-facing ALBs) orkubernetes.io/role/internal-elb
(for internal ALBs). Subnets with these tags will be favored when selecting subnets for the ALBs. Additionally you can tag EC2 subnets withkubernetes.io/cluster/<cluster-id>
, which will be prioritized. If there are two possible subnets for a single Availability Zone then the first subnet, lexicographically sorted by ID, will be selected.
When the controller learns about new ingress resources, it uses the hosts specified in it to automatically determine the most specific, valid certificates to use. The certificates has to be valid for at least 7 days. An example ingress:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: test-app
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
The Application Load Balancer created by the controller will have both an HTTP listener and an HTTPS listener. The latter will use the automatically selected certificates.
By default the ingress-controller will aggregate all ingresses under as few
Application Load Balancers as possible (unless running with
--disable-sni-support
). If you like to provision an Application Load Balancer
that is unique for an ingress you can use the annotation
zalando.org/aws-load-balancer-shared: "false"
.
The new Application Load Balancers have a custom tag marking them as managed load balancers to differentiate them from other load balancers. The tag looks like this:
`kubernetes:application` = `kube-ingress-aws-controller`
They also share the kubernetes.io/cluster/<cluster-id>
tag with other resources from the cluster where it belongs.
As a second option you can specify the Amazon Resource Name (ARN) of the desired certificate with an annotation like the one shown here:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
annotations:
zalando.org/aws-load-balancer-ssl-cert: arn:aws:acm:eu-central-1:123456789012:certificate/f4bd7ed6-bf23-11e6-8db1-ef7ba1500c61
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
You can select the Application Load Balancer Scheme with an annotation like the one shown here:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
annotations:
zalando.org/aws-load-balancer-scheme: internal
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
You can only select from internet-facing
(default) and internal
options.
Since >=v0.10.5
, you can create Ingress objects with host
rules,
that have the .cluster.local
and the controller will not create an
ALB for this.
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
spec:
rules:
- host: test-app.skipper.cluster.local
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
If you pass --cluster-local-domain=".cluster.local"
, you can change
what domain is considered cluster internal. If you're using the deny
internal traffic feature, you might
want to sync this configuration with the --internal-domains
one.
Since >=v0.11.18
the controller supports the flag
--deny-internal-domains
. It's a boolean config item that when enabled
configures the ALBs' cloudformation templates with a
AWS::ElasticLoadBalancingV2::ListenerRule
resource.
This rule will be configured with the condition
values from the --internal-domains
flag and the
action fixedresponseconfig
with the respective response
--deny-internal-domains-response
flags. This feature is not enabled by
default. The following are the default values to its config flags:
internal-domains
:*.cluster.local
deny-internal-domains
:false
(same as explicitly passing--no-deny-internal-domains
)deny-internal-domains-response
:Unauthorized
deny-internal-domains-response-content-type
:text/plain
deny-internal-domains-response-status-code
:401
Note that --internal-domains
differs from --cluster-local-domain
,
which is used exclusively to avoid load balancers creation for the
cluster internal
domain.
The --internal-domains
flag can be set multiple times and accept AWS'
wildcard characters. Check the AWS' docs on the Host Header
config for more details.
This feature is not supported by NLBs.
Example:
Running the controller with --deny-internal-domains
and
--internal-domains=*.cluster.local
will generate a rule in the ALB
that matches any request to domains ending in .cluster.local
and answer
the request with an HTTP 401 Unauthorized.
You can select the default
SSLPolicy,
with the flag --ssl-policy=ELBSecurityPolicy-TLS-1-2-2017-01
. This
choice can be overriden by the Kubernetes Ingress annotation
zalando.org/aws-load-balancer-ssl-policy
to any valid value. Valid
values will be checked by the controller.
Example:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
annotations:
zalando.org/aws-load-balancer-ssl-policy: ELBSecurityPolicy-FS-2018-06
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
The controller will normally automatically detect the SecurityGroup to
use. Auto detection is done by filtering all SecurityGroups with AWS
Tags. The kubernetes.io/cluster/<cluster-id>
tag of the Security
Group should match clusterID for the controller node with value
owned
and kubernetes:application
tag should match the value
kube-ingress-aws-controller
.
If you want to override the detected SecurityGroup, you can set a
SecurityGroup of your choice with the
zalando.org/aws-load-balancer-security-group
annotation like the
shown here:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
annotations:
zalando.org/aws-load-balancer-security-group: sg-somegroupeid
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
It is possible to define WAF associations for the created load balancers. The WAF Web ACLs need to be created separately via CloudFormation or the AWS Console, and they can be referenced either as a global startup configuration of the controller, or as ingress specific settings in the ingress object with an annotation. The ingress annotation overrides the global setting, and the controller will create separate load balancers for those ingresses using a separate WAF association.
The controller supports two versions of AWS WAF:
- WAF (v1 or "classic"): the Web ACL is identified by a UUID
- WAFv2: the Web ACL is identified by its ARN, prefixed with
arn:aws:wafv2:
Only one WAF association can be used for a load balancer, and the same command line flag and ingress annotation is used for both versions, only the format of the value differs.
kube-ingress-aws-controller --aws-waf-web-acl-id=arn:aws:wafv2:eu-central-1:123456789012:regional/webacl/test-waf-acl/12345678-abcd-efgh-ijkl-901234567890
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: myingress
annotations:
zalando.org/aws-waf-web-acl-id: arn:aws:wafv2:eu-central-1:123456789012:regional/webacl/test-waf-acl/12345678-abcd-efgh-ijkl-901234567890
spec:
rules:
- host: test-app.example.org
http:
paths:
- backend:
serviceName: test-app-service
servicePort: main-port
When the controller detects that a managed load balancer for the current cluster doesn't have a matching ingress resource anymore, it deletes all the previously created resources.
Deletion may take up to about 30 minutes. This ensures proper draining of connections on the lodadbalancers and allows for DNS TTLs to expire.
This project provides a Makefile
that you can use to build either a binary or a Docker image.
To build a binary for the Linux operating system, simply run make
or make build.linux
.
To create a Docker image instead, execute make build.docker
. You can then push your Docker image to the Docker
registry of your choice.
To deploy the ingress controller, use the example YAML as the descriptor. You can customize the image used in the example YAML file.
We provide registry.opensource.zalan.do/teapot/kube-ingress-aws-controller:latest
as a publicly usable Docker image
built from this codebase. You can deploy it with 2 easy steps:
- Replace the placeholder for your region inside the example YAML, for ex.,
eu-west-1
- Use kubectl to execute the command
kubectl apply -f deploy/ingress-controller.yaml
If you use Kops to create your cluster, please use our deployment guide for Kops
In some cases it might be useful to run multiple instances of this controller:
- Isolating internal vs external traffic
- Using a different set of traffic processing nodes
- Using different frontend routers (e.g.: Skipper and Traefik)
You can use the flag --controller-id
to set a token that will be used to isolate resources between controller instances.
This value will be used to tag those resources.
If you don't pass an ID, the default kube-ingress-aws-controller
will be used.
Usually you would want to combine this flag with ingress-class-filter
so different types of ingresses are associated with the different controllers.
To make kube-ingress-aws-controller
manage both specific ingress class and an empty one (or ingresses without ingress class annotation) add an empty class to the list. For example to manage ingress class foo
and ingresses without class set parameter like this --ingress-class-filter=foo,
(notice the comma in the end).
Ingress classes defined in the spec of ingresses at spec.ingressClassName
(Kubernetes Documentation) will take priority over the annotation, if both are supplied.
In order to match the default (empty) ingress group, both must be empty."
By default the port 9999 is used as both health check and target port. This means that Skipper or any other traffic router you're using needs to be listening on that port.
If you want to change the default ports, you can control it using the
-target-port
and -health-check-port
flags.
If you want to use an HTTPS enabled target port, use the -target-https
flag.
This will only affect ALBs, NLBs ignore this flag.
By default, the controller will expose both HTTP and HTTPS ports on the load balancer, and forward both listeners to the target port. Setting the flag -redirect-http-to-https
will instead configure the HTTP listener to emit a 301 redirect for any request received, with the destination location being the same URL but with the HTTPS scheme vs. HTTP. The specifics are described in the relevant aws documentation.
The controller used to have only the --health-check-port
flag available, and would use the same port as health check and the target port.
Those ports are now configured individually. If you relied on this behavior, please include the --target-port
in your configuration.
The Ingress Controller's responsibility is limited to managing load balancers, as described above. To have a fully functional setup, additionally to the ingress controller, you can use Skipper to route the traffic to the application. The setup follows what's described here.
You can deploy skipper
as a DaemonSet
using another example YAML by executing the following command:
kubectl apply -f deploy/skipper.yaml
To complete the setup, you'll need to fulfill some additional requirements regarding security groups and IAM roles; more info here.
To have convenient DNS names for your application, you can use the Kubernetes-Incubator project, external-dns. It's not strictly necessary for this Ingress Controller to work, though.
We welcome your contributions, ideas and bug reports via issues and pull requests; here are those Contributor guidelines again.
Check our MAINTAINERS file for email addresses.
We welcome your security reports please checkout our SECURITY.md.
The MIT License (MIT) Copyright © [2017] Zalando SE, https://tech.zalando.com
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.