ndots creates overhead as every pod creates 5 concurrent connections
that are forwarded to sky dns. Under some circumstances dnsmasq may
prevent forwarding traffic with "Maximum number of concurrent DNS
queries reached" in the logs.
This patch allows to configure the number of concurrent forwarded DNS
queries "dns-forward-max" as well as "cache-size" leaving the default
values as they were before.
Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>
Also place in global vars and do not repeat the kube_*_config_dir
and kube_namespace vars for better code maintainability and UX.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
In order to enable offline/intranet installation cases:
* Move DNS/resolvconf configuration to preinstall role. Remove
skip_dnsmasq_k8s var as not needed anymore.
* Preconfigure DNS stack early, which may be the case when downloading
artifacts from intranet repositories. Do not configure
K8s DNS resolvers for hosts /etc/resolv.conf yet early (as they may be
not existing).
* Reconfigure K8s DNS resolvers for hosts only after kubedns/dnsmasq
was set up and before K8s apps to be created.
* Move docker install task to early stage as well and unbind it from the
etcd role's specific install path. Fix external flannel dependency on
docker role handlers. Also fix the docker restart handlers' steps
ordering to match the expected sequence (the socket then the service).
* Add default resolver fact, which is
the cloud provider specific and remove hardcoded GCE resolver.
* Reduce default ndots for hosts /etc/resolv.conf to 2. Multiple search
domains combined with high ndots values lead to poor performance of
DNS stack and make ansible workers to fail very often with the
"Timeout (12s) waiting for privilege escalation prompt:" error.
* Update docs.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
* Add an option to deploy K8s app to test e2e network connectivity
and cluster DNS resolve via Kubedns for nethost/simple pods
(defaults to false).
* Parametrize existing k8s apps templates with kube_namespace and
kube_config_dir instead of hardcode.
* For CoreOS, ensure nameservers from inventory to be put in the
first place to allow hostnet pods connectivity via short names
or FQDN and hostnet agents to pass as well, if netchecker
deployed.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
* Add dns_replicas, dns_memory/cpu_limit/requests vars for
dns related apps.
* When kube_log_level=4, log dnsmasq queries as well.
* Add log level control for skydns (part of kubedns app).
* Add limits/requests vars for dnsmasq (part of kubedns app) and
dnsmasq daemon set.
* Drop string defaults for kube_log_level as it is int and
is defined in the global vars as well.
* Add docs
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
When download_run_once with download_localhost is used, docker is
expected to be running on the delegate localhost. That may be not
the case for a non localhost delegate, which is the kube-master
otherwise. Then the dnsmasq role, had it been invoked early before
deployment starts, would fail because of the missing docker dependency.
* Fix that dependency on docker and do not pre download dnsmasq image
for the dnsmasq role, if download_localhost is disabled.
* Remove become: false for docker CLI invocation because that's not
the common pattern to allow users access docker CLI w/o sudo.
* Fix opt bin path hack for localhost delegate to ignore errors when
it fails with "sudo password required" otherwise.
* Describe download_run_once with download_localhost use case in docs
as well.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Use cloud-init config to replace /etc/resolv.conf with the
content for kubelet to properly configure hostnet pods.
Do not use systemd-resolved yet, see
https://coreos.com/os/docs/latest/configuring-dns.html
"Only nss-aware applications can take advantage of the
systemd-resolved cache. Notably, this means that statically
linked Go programs and programs running within Docker/rkt
will use /etc/resolv.conf only, and will not use the
systemd-resolve cache."
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
According to http://kubernetes.io/docs/user-guide/images/ :
By default, the kubelet will try to pull each image from the
specified registry. However, if the imagePullPolicy property
of the container is set to IfNotPresent or Never, then a local\
image is used (preferentially or exclusively, respectively).
Use IfNotPresent value to allow images prepared by the download
role dependencies to be effectively used by kubelet without pull
errors resulting apps to stay blocked in PullBackOff/Error state
even when there are images on the localhost exist.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Pre download all required container images as roles' deps.
Drop unused flannel-server-helper images pre download.
Improve pods creation post-install test pre downloaded busybox.
Improve logs collection script with kubectl describe, fix sudo/etcd/weave
commands.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
test to change the machine type
Revert "test to change the machine type"
This reverts commit 7a91f1b5405a39bee6cb91940b09a0b0f9d3aee1.
use google dns server when no upstream dns are defined
comment upstream_dns_servers
update documentation
remove deprecated kubelet flags
Revert "remove deprecated kubelet flags"
This reverts commit 21e3b893c896d0291c36a07d0414f4cb88b8d8ac.
Initially this was removed, but it turns out that services that
perform reverse lookups (such as MariaDB) will encounter severe
performance degredation with this disabled.
* Add a var for ndots (default 5) and put it hosts' /etc/resolv.conf.
* Poke kube dns container image to v1.7
* In order to apply changes to kubelet, notify it to
be restarted on changes made to /etc/resolv.conf. Ignore errors as the kubelet
may yet to be present up to the moment of the notification being processed.
* Remove unnecessary kubelet restart for master role as the node role ensures
it is up and running. Notify master static pods waiters for apiserver,
scheduler, controller-manager instead.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
- Update docs and a drawing to clarify DNS setup.
- Change order of nameservers placement to match
changes in https://github.com/kubespray/kargo/pull/501
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Change additional dnsmasq opts:
- Adjust caching size and TTL
- Disable resolve conf to not create loops
- Change dnsPolicy to default (similarly to kubedns's dnsmasq). The
ClusterFirst should not be used to not create loops
- Disable negative NXDOMAIN replies to be cached
- Make its very installation as optional step (enabled by default).
If you don't want more than 3 DNS servers, including 1 for K8s, disable
it.
- Add docs and a drawing to clarify DNS setup.
- Fix stdout logs for dnsmasq/kubedns app configs
- Add missed notifies to resolvconf -u handler
- Fix idempotency of resolvconf head file changes
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Removed api-version from kube.py because it is deprecated.
Updating both kube.py because dnsmasq one is actually used.
Fixed name back to kubedns for checking its resource.
Move updating resolvconf to the network restart handler to
ensure changes applied to the /etc/resolv.conf.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
* Ensure additional nameserver/search, if defined as vars.
* Don't backup changed dhclient hooks as they are going to be
executed by dhclient as well, which is not what we want.
* For debian OS family only:
- Rename nodnsupdate hook the resolvconf hook to be sourced always
before it.
- Ensure dhclient restarted via network restart to apply the
nodnsupdate hook.
* For rhel OS family, the fix TBD, it doesn't work the same way.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Rename nodnsupdate hook the resolvconf hook to be sourced always
before it.
Ensure dhclient restarted via network restart to apply the
nodnsupdate hook.
Ensure additional nameserver/search, if defined as vars.
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
If resolvconf was installed and then removed, the file
/etc/resolvconf/resolv.conf.d/head remains in the filesystem
- change discovery of 'resolvconf' executable to check if it
can be located with 'which resolvconf' command or not.
Sergii Golovatiuk
Alexander Block
Bogdan Dobrelya
Bogdan Dobrelya
Antoine Legrand
Matthew Mosesohn
Chad Swenson
Smana
Özgür Caner
Ivan Shvedunov
dis
Stig Telfer
teuto.net Netzdienste GmbH
Smaine Kahlouch
ant31
Antoine Legrand
Greg Althaus