Linux DNS error
Linux DNS error injects chaos to disrupt the DNS resolution on a Linux machine.
Use cases
- Induces DNS error on the target Linux machines.
- Simulates loss of access to host by blocking the DNS resolution of host names.
note
- This fault can be executed on Ubuntu 16 or higher, Debian 10 or higher, CentOS 7 or higher, RHEL 7 or higher, Fedora 30 or higher, and openSUSE LEAP 15.4 or higher.
- The
linux-chaos-infrastructure
systemd service should be in an active state, and the infrastructure should be inCONNECTED
state.
Fault permissions
The fault uses the root
Linux user and root
user group.
Optional tunables
Tunable | Description | Notes |
---|---|---|
hostNames | List of the target host names or keywords. For example, google.com,litmuschaos.io . | If not provided, all host names are targeted. |
matchScheme | Determines whether the DNS query has to exactly match one of the targets or can have any of the targets as substring. It can be exact or substring . | If not provided, it is set to exact |
upstreamServer | URL of the DNS upstream server. | |
dnsPort | Port of the DNS server. | |
duration | Duration through which chaos is injected into the target resource. Should be provided in [numeric-hours]h[numeric-minutes]m[numeric-seconds]s format. | Default: 30s . Examples: 1m25s , 1h3m2s , 1h3s |
rampTime | Period to wait before and after injecting chaos. Should be provided in [numeric-hours]h[numeric-minutes]m[numeric-seconds]s format. | Default: 0s . Examples: 1m25s , 1h3m2s , 1h3s |
Host names
The hostNames
input variable subjects the comma-separated host names to chaos.
The following YAML snippet illustrates the use of this input variable:
# target host names
apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
name: linux-dns-error
labels:
name: dns-error
spec:
dnsChaos/inputs:
hostNames: 'litmuschaos.io,google.com'
Match scheme
The matchScheme
input variable either exactly matches one of the targets to the DNS query or has any of the targets as a substring of the DNS query.
The following YAML snippet illustrates the use of this input variable:
# dns query match scheme
apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
name: linux-dns-error
labels:
name: dns-error
spec:
stressChaos/inputs:
matchScheme: 'exact'