Apache Tomcat is an open-source web server designed to host and run Java-based web applications. It is a lightweight server with a good performance for applications running in production environments.
[Overview of Apache Tomcat](http://tomcat.apache.org/)
Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.
This chart bootstraps a [Tomcat](https://github.com/bitnami/containers/tree/main/bitnami/tomcat) deployment on a [Kubernetes](https://kubernetes.io) cluster using the [Helm](https://helm.sh) package manager.
Tomcat implements several Java EE specifications including Java Servlet, JavaServer Pages, Java EL, and WebSocket, and provides a "pure Java" HTTP web server environment for Java code to run in.
Bitnami charts can be used with [Kubeapps](https://kubeapps.dev/) for deployment and management of Helm Charts in clusters.
Looking to use Apache Tomcat in production? Try [VMware Application Catalog](https://bitnami.com/enterprise), the enterprise edition of Bitnami Application Catalog.
These commands deploy Tomcat on the Kubernetes cluster in the default configuration. The [Parameters](#parameters) section lists the parameters that can be configured during installation.
| `podManagementPolicy` | podManagementPolicy to manage scaling operation of pods (only in StatefulSet mode) | `""` |
| `tolerations` | Tolerations for pod assignment. Evaluated as a template. | `[]` |
| `topologySpreadConstraints` | Topology Spread Constraints for pod assignment spread across your cluster among failure-domains. Evaluated as a template | `[]` |
| `extraPodSpec` | Optionally specify extra PodSpec | `{}` |
| `extraVolumes` | Optionally specify extra list of additional volumes for Tomcat pods in Deployment | `[]` |
| `extraVolumeClaimTemplates` | Optionally specify extra list of additional volume claim templates for Tomcat pods in StatefulSet | `[]` |
| `extraVolumeMounts` | Optionally specify extra list of additional volumeMounts for Tomcat container(s) | `[]` |
| `initContainers` | Add init containers to the Tomcat pods. | `[]` |
| `sidecars` | Add sidecars to the Tomcat pods. | `[]` |
| `ingress.hostname` | Default host for the ingress resource | `tomcat.local` |
| `ingress.annotations` | Additional annotations for the Ingress resource. To enable certificate autogeneration, place here your cert-manager annotations. | `{}` |
| `ingress.tls` | Enable TLS configuration for the hostname defined at `ingress.hostname` parameter | `false` |
| `ingress.extraHosts` | The list of additional hostnames to be covered with this ingress record. | `[]` |
| `ingress.extraTls` | The tls configuration for additional hostnames to be covered with this ingress record. | `[]` |
| `ingress.extraPaths` | Any additional arbitrary paths that may need to be added to the ingress under the main host. | `[]` |
| `ingress.selfSigned` | Create a TLS secret for this ingress record using self-signed certificates generated by Helm | `false` |
| `ingress.ingressClassName` | IngressClass that will be be used to implement the Ingress (Kubernetes 1.18+) | `""` |
| `ingress.secrets` | If you're providing your own certificates, please use this to add the certificates as secrets | `[]` |
| `ingress.extraRules` | Additional rules to be covered with this ingress record | `[]` |
| `ingress.apiVersion` | Force Ingress API version (automatically detected if not set) | `""` |
| `ingress.path` | Ingress path | `/` |
| `ingress.pathType` | Ingress path type | `ImplementationSpecific` |
| `volumePermissions.image.digest` | Init container volume-permissions image digest in the way sha256:aa.... Please note this parameter, if set, will override the tag | `""` |
The above parameters map to the env variables defined in [bitnami/tomcat](https://github.com/bitnami/containers/tree/main/bitnami/tomcat). For more information please refer to the [bitnami/tomcat](https://github.com/bitnami/containers/tree/main/bitnami/tomcat) image documentation.
Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`. For example,
The above command sets the Tomcat management username and password to `manager` and `password` respectively.
> NOTE: Once this chart is deployed, it is not possible to change the application's access credentials, such as usernames or passwords, using Helm. To change these application credentials after deployment, delete any persistent volumes (PVs) used by the chart and re-deploy it, or use the application's built-in administrative tools if available.
Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,
> **Tip**: You can use the default [values.yaml](values.yaml)
## Configuration and installation details
### [Rolling vs Immutable tags](https://docs.bitnami.com/containers/how-to/understand-rolling-tags-containers/)
It is strongly recommended to use immutable tags in a production environment. This ensures your deployment does not change automatically if the same tag is updated with a different image.
Bitnami will release a new chart updating its containers if a new version of the main container, significant changes, or critical vulnerabilities exist.
### Use a different Tomcat version
To modify the application version used in this chart, specify a different version of the image using the `image.tag` parameter and/or a different repository using the `image.repository` parameter. Refer to the [chart documentation for more information on these parameters and how to use them with images from a private registry](https://docs.bitnami.com/kubernetes/infrastructure/tomcat/configuration/change-image-version/).
### Add extra environment variables
To add extra environment variables (useful for advanced operations like custom init scripts), use the `extraEnvVars` property.
```yaml
extraEnvVars:
- name: LOG_LEVEL
value: DEBUG
```
Alternatively, define a ConfigMap or a Secret with the environment variables. To do so, use the `extraEnvVarsCM` or the `extraEnvVarsSecret` values.
### Use Sidecars and Init Containers
If additional containers are needed in the same pod (such as additional metrics or logging exporters), they can be defined using the `sidecars` config parameter. Similarly, extra init containers can be added using the `initContainers` parameter.
Refer to the chart documentation for more information on, and examples of, configuring and using [sidecars and init containers](https://docs.bitnami.com/kubernetes/infrastructure/tomcat/configuration/configure-sidecar-init-containers/).
### Set Pod affinity
This chart allows you to set custom Pod affinity using the `affinity` parameter. Find more information about Pod's affinity in the [Kubernetes documentation](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity).
As an alternative, use one of the preset configurations for pod affinity, pod anti-affinity, and node affinity available at the [bitnami/common](https://github.com/bitnami/charts/tree/main/bitnami/common#affinities) chart. To do so, set the `podAffinityPreset`, `podAntiAffinityPreset`, or `nodeAffinityPreset` parameters.
## Persistence
The [Bitnami Tomcat](https://github.com/bitnami/containers/tree/main/bitnami/tomcat) image stores the Tomcat data and configurations at the `/bitnami/tomcat` path of the container.
Persistent Volume Claims (PVCs) are used to keep the data across deployments. This is known to work in GCE, AWS, and minikube.
See the [Parameters](#parameters) section to configure the PVC or to disable persistence.
### Adjust permissions of persistent volume mountpoint
As the image run as non-root by default, it is necessary to adjust the ownership of the persistent volume so that the container can write data into it.
By default, the chart is configured to use Kubernetes Security Context to automatically change the ownership of the volume. However, this feature does not work in all Kubernetes distributions.
As an alternative, this chart supports using an init container to change the ownership of the volume before mounting it in the final destination.
You can enable this init container by setting `volumePermissions.enabled` to `true`.
## Troubleshooting
Find more information about how to deal with common errors related to Bitnami's Helm charts in [this troubleshooting guide](https://docs.bitnami.com/general/how-to/troubleshoot-helm-chart-issues).
## Upgrading
### To 10.0.0
Some of the chart values were changed to adapt to the latest Bitnami standards. More specifically:
-`containerPort` was changed to `containerPorts.http`
-`service.port` was changed to `service.ports.http`
No issues should be expected when upgrading.
### To 8.0.0
- Chart labels were adapted to follow the [Helm charts standard labels](https://helm.sh/docs/chart_best_practices/labels/#standard-labels).
- Ingress configuration was also adapted to follow the Helm charts best practices.
- This version also introduces `bitnami/common`, a [library chart](https://helm.sh/docs/topics/library_charts/#helm) as a dependency. More documentation about this new utility could be found [here](https://github.com/bitnami/charts/tree/main/bitnami/common#bitnami-common-library-chart). Please, make sure that you have updated the chart dependencies before executing any upgrade.
Consequences:
- Backwards compatibility is not guaranteed. However, you can easily workaround this issue by removing Tomcat deployment before upgrading (the following example assumes that the release name is `tomcat`):
[On November 13, 2020, Helm v2 support formally ended](https://github.com/helm/charts#status-of-the-project). This major version is the result of the required changes applied to the Helm Chart to be able to incorporate the different features added in Helm v3 and to be consistent with the Helm project itself regarding the Helm v2 EOL.
[Learn more about this change and related upgrade considerations](https://docs.bitnami.com/kubernetes/infrastructure/tomcat/administration/upgrade-helm3/).
### To 5.0.0
This release updates the Bitnami Tomcat container to `9.0.26-debian-9-r0`, which is based on Bash instead of Node.js.
### To 2.1.0
Tomcat container was moved to a non-root approach. There shouldn't be any issue when upgrading since the corresponding `securityContext` is enabled by default. Both the container image and the chart can be upgraded by running the command below:
