path: root/docs/troubleshooting.txt

The services has to be running
------------------------------
  Etcd:
    - etcd 

  Node:
    - origin-node
 
  Master nodes:
    - origin-master-api
    - origin-master-controllers
    - origin-master is not running

  Required Services:
    - lvm2-lvmetad.socket 
    - lvm2-lvmetad.service
    - docker                                    - it may happen that service is alive according to systemd, but does not respond ('docker ps' timeouts)
    - NetworkManager
    - firewalld
    - dnsmasq
    - openvswitch
 
  Extra Services:
    - ssh
    - ntp
    - openvpn
    - ganesha (on master nodes, optional)

Pods has to be running
----------------------
  Kubernetes System
    - kube-service-catalog/apiserver
    - kube-service-catalog/controller-manager
  
  OpenShift Main Services
    - default/docker-registry
    - default/registry-console
    - default/router (3 replicas)
    - openshift-template-service-broker/api-server (daemonset, on all nodes)

  OpenShift Secondary Services
    - openshift-ansible-service-broker/asb
    - openshift-ansible-service-broker/asb-etcd

  GlusterFS
     - glusterfs-storage (daemonset, on all storage nodes)
     - glusterblock-storage-provisioner-dc
     - heketi-storage

  Metrics (openshift-infra):
    - hawkular-cassandra
    - hawkular-metrics
    - heapster
    

Debugging
=========
 - Ensure system consistency as explained in 'consistency.txt' (incomplete)
 - Check current pod logs and possibly logs for last failed instance
        oc logs <pod name> --tail=100 [-p]                  - dc/name or ds/name as well
 - Verify initialization steps (check if all volumes are mounted)
        oc describe <pod name>
 - Security (SCC) problems are visible if replica controller is queried
        oc -n adei get  rc/mysql-1 -o yaml
 - It worth looking the pod environment
        oc env po <pod name> --list
 - It worth connecting running container with 'rsh' session and see running processes,
 internal logs, etc. The 'debug' session will start a new instance of the pod.
 - If try looking if corresponding pv/pvc are bound. Check logs for pv.
    * Even if 'pvc' is bound. The 'pv' may have problems with its backend.
    * Check logs here: /var/lib/origin/plugins/kubernetes.io/glusterfs/
 - Another frequent problems is failing 'postStart' hook. Or 'livenessProbe'. As it
 immediately crashes it is not possible to connect. Remedies are:
    * Set larger initial delay to check the probe.
    * Try to remove hook and execute it using 'rsh'/'debug'
 - Determine node running the pod and check the host logs in '/var/log/messages'
    * Particularly logs of 'origin-master-controllers' are of interest
 - Check which docker images are actually downloaded on the node
        docker images

network
=======
 - There is a NetworkManager script which should adjust /etc/resolv.conf to use local dnsmasq server.
 This is based on  '/etc/NetworkManager/dispatcher.d/99-origin-dns.sh' which does not play well 
 if OpenShift is running on non-default network interface. I provided a patched version, but it
 worth verifying 
    * that nameserver is pointing to the host itself (but not localhost, this is important
    to allow running pods to use it)
    * that correct upstream nameservers are listed in '/etc/dnsmasq.d/origin-upstream-dns.conf'
    * that correct upstream nameservers are listed in '/etc/origin/node/resolv.conf'
    * In some cases, it was necessary to restart dnsmasq (but it could be also for different reasons)
 If script misbehaves, it is possible to call it manually like that
    DEVICE_IFACE="eth1" ./99-origin-dns.sh eth1 up


etcd (and general operability)
====
 - Few of this sevices may seem running accroding to 'systemctl', but actually misbehave. Then, it 
 may be needed to restart them manually. I have noticed it with 
    * lvm2-lvmetad.socket       (pvscan will complain on problems)
    * node-origin
    * glusterd in container     (just kill the misbehaving pod, it will be recreated)
    * etcd               but BEWARE of too entusiastic restarting:
 - However, restarting etcd many times is BAD as it may trigger a severe problem with 
 'kube-service-catalog/apiserver'. The bug description is here
        https://github.com/kubernetes/kubernetes/issues/47131
 - Due to problem mentioned above, all 'oc' queries are very slow. There is not proper
 solution suggested. But killing the 'kube-service-catalog/apiserver' helps for a while.
 The pod is restarted and response times are back in order.
    * Another way to see this problem is quering 'healthz' service which would tell that
    there is too many clients and, please, retry later.
        curl -k https://apiserver.kube-service-catalog.svc/healthz

 - On node crash, the etcd database may get corrupted. 
    * There is no easy fix. Backup/restore is not working.
    * Easiest option is to remove the failed etcd from the cluster.
        etcdctl3 --endpoints="192.168.213.1:2379" member list
        etcdctl3 --endpoints="192.168.213.1:2379" member remove <hexid>
    * Add it to [new_etcd] section in inventory and run openshift-etcd to scale-up etcd cluster.
 
 - There is a helth check provided by the cluster
    curl -k https://apiserver.kube-service-catalog.svc/healthz
 it may complain about etcd problems. It seems triggered by OpenShift upgrade. The real cause and
 remedy is unclear, but the installation is mostly working. Discussion is in docs/upgrade.txt
 
 - There is also a different etcd which is integral part of the ansible service broker: 
 'openshift-ansible-service-broker/asb-etcd'. If investigated with 'oc logs' it complains 
 on:
        2018-03-07 20:54:48.791735 I | embed: rejected connection from "127.0.0.1:43066" (error "tls: failed to verify client's certificate: x509: certificate signed by unknown authority", ServerName "")
        WARNING: 2018/03/07 20:54:48 Failed to dial 0.0.0.0:2379: connection error: desc = "transport: authentication handshake failed: remote error: tls: bad certificate"; please retry.
 Nevertheless, it seems working without much trouble. The error message seems caused by
 certificate verification code which introduced in etcd 3.2. There are multiple bug repports on
 the issue.
 
pods (failed pods, rogue namespaces, etc...)
====
 - The 'pods' scheduling may fail on one (or more) of the nodes after long waiting with 'oc logs' reporting
 timeout. The 'oc describe' reports 'failed to create pod sandbox'. This can be caused by failure to clean-up 
 after terminated pod properly. It causes rogue network interfaces to remain in OpenVSwitch fabric. 
  * This can be determined by errors reported using 'ovs-vsctl show' or present in the log '/var/log/openvswitch/ovs-vswitchd.log' 
    which may quickly grow over 100MB quickly. 
        could not open network device vethb9de241f (No such device)
  * The work-around is to delete rogue interfaces with 
        ovs-vsctl del-port br0 <iface>
    More info:
        ovs-ofctl -O OpenFlow13 show br0
        ovs-ofctl -O OpenFlow13 dump-flows br0
    This does not solve the problem, however. The new interfaces will get abandoned by OpenShift.
  * The issue is discussed here:
        https://bugzilla.redhat.com/show_bug.cgi?id=1518684
        https://bugzilla.redhat.com/show_bug.cgi?id=1518912
        
 - After crashes / upgrades some pods may end up in 'Error' state. This is quite often happen to
    * kube-service-catalog/controller-manager
    * openshift-template-service-broker/api-server
 Normally, they should be deleted. Then, OpenShift will auto-restart pods and they likely will run without problems.
    for name in  $(oc get pods -n openshift-template-service-broker | grep Error | awk '{ print $1 }' ); do oc -n openshift-template-service-broker delete po $name; done
    for name in  $(oc get pods -n kube-service-catalog | grep Error | awk '{ print $1 }' ); do oc -n kube-service-catalog delete po $name; done 
 
 - Other pods will fail with 'ImagePullBackOff' after cluster crash. The problem is that ImageStreams populated by 'builds' will 
 not be recreated automatically. By default OpenShift docker registry is stored on ephemeral disks and is lost on crash. The build should be 
 re-executed manually.
        oc -n adei start-build adei

 - Furthermore, after long outtages the CronJobs will stop functioning. The reason can be found by analyzing '/var/log/messages' or specially
        systemctl status origin-master-controllers
  it will contain something like:
        'Cannot determine if <namespace>/<cronjob> needs to be started: Too many missed start time (> 100). Set or decrease .spec.startingDeadlineSeconds or check clock skew.'
  * The reason is that after 100 missed (or failed) launch periods it will stop trying to avoid excive load. The remedy is set 'startingDeadlineSeconds'
  which tells the system that if cronJob has failed to start in the allocated interval we stop trying until the next start period. Then, 100 is only 
  counted the specified period. I.e. we should set period bellow the 'launch period / 100'.
        https://github.com/kubernetes/kubernetes/issues/45825
  * The running CronJobs can be easily patched with
        oc -n adei patch cronjob/adei-autogen-update --patch '{ "spec": {"startingDeadlineSeconds": 120 }}'
  
 - Sometimes there is rogue namespaces in 'deleting' state. This is also hundreds of reasons, but mainly
    * Crash of both masters during population / destruction of OpenShift resources
    * Running of 'oc adm diagnostics'
  It is unclear how to remove them manually, but it seems if we run
    * OpenShift upgrade, the namespaces are gone (but there could be a bunch of new problems).
    * ... i don't know if install, etc. May cause the trouble...

 - There is also rogue pods (mainly due to some problems with unmounting lost storage), etc. If 'oc delete' does not
 work for a long time. It worth
    * Determining the host running failed pod with 'oc get pods -o wide'
    * Going to the pod and killing processes and stopping the container using docker command
    * Looking in the '/var/lib/origin/openshift.local.volumes/pods' for the remnants of the container
        - This can be done with 'find . -name heketi*' or something like...
        - There could be problematic mounts which can be freed with lazy umount
        - The folders for removed pods may (and should) be removed.

 - Looking into the '/var/log/messages', it is sometimes possible to spot various erros like
    * Orphaned pod "212074ca-1d15-11e8-9de3-525400225b53" found, but volume paths are still present on disk.
        The volumes can be removed in '/var/lib/origin/openshift.local.volumes/pods' on the corresponding node
    * PodSandbox "aa28e9c7605cae088838bb4c9b92172083680880cd4c085d93cbc33b5b9e8910" from runtime service failed: ...
        - We can find and remove the corresponding container (the short id is just first letters of the long id)
                docker ps -a | grep aa28e9c76
                docker rm <id>
        - We further can just destroy all containers which are not running (it will actually try to remove all,
        but just error message will be printed for running ones)
                docker ps -aq --no-trunc | xargs docker rm




Builds
======
 - After changing storage for integrated docker registry, it may refuse builds with HTTP error 500. It is necessary
 to run:
    oadm policy reconcile-cluster-roles


Storage
=======
 - Running a lot of pods may exhaust available storage. It worth checking if 
    * There is enough Docker storage for containers (lvm)
    * There is enough Heketi storage for dynamic volumes (lvm)
    * The root file system on nodes still has space for logs, etc. 
  Particularly there is a big problem for ansible-ran virtual machines. The system disk is stored
  under '/root/VirtualBox VMs' and is not cleaned/destroyed unlike second hard drive on 'vagrant
  destroy'. So, it should be cleaned manually.
  
 - Problems with pvc's can be evaluated by running 
        oc  -n openshift-ansible-service-broker describe pvc etcd
   Furthermore it worth looking in the folder with volume logs. For each 'pv' it stores subdirectories
   with pods executed on this host which are mount this pod and holds the log for this pods.
        /var/lib/origin/plugins/kubernetes.io/glusterfs/

 - Heketi is problematic.
    * Worth checking if topology is fine and running.
        heketi-cli -s http://heketi-storage-glusterfs.openshift.suren.me --user admin --secret "$(oc get secret heketi-storage-admin-secret -n glusterfs -o jsonpath='{.data.key}' | base64 -d)"
 - Furthermore, the heketi gluster volumes may be started, but with multiple bricks offline. This can
 be checked with 
        gluster volume status <vol> detail
    * If not all bricks online, likely it is just enought to restart the volume
        gluster volume stop <vol>
        gluster volume start <vol>
    * This may break services depending on provisioned 'pv' like 'openshift-ansible-service-broker/asb-etcd'
    
 - If something gone wrong, heketi may end-up creating a bunch of new volumes, corrupt database, and crash
 refusing to start. Here is the recovery procedure.
    * Sometimes, it is still possible to start by setting 'HEKETI_IGNORE_STALE_OPERATIONS' environmental
    variable on the container.
        oc -n glusterfs env dc  heketi-storage -e HEKETI_IGNORE_STALE_OPERATIONS=true
    * Even if it works, it does not solve the main issue with corruption. It is necessary to start a 
    debugging pod for heketi (oc debug) export corrupted databased, fix it, and save back. Having
    database backup could save a lot of hussle to find that is amiss.
        heketi db export --dbfile heketi.db --jsonfile /tmp/q.json
        oc cp glusterfs/heketi-storage-3-jqlwm-debug:/tmp/q.json q.json
        cat q.json | python -m json.tool > q2.json
        ...... Fixing .....
        oc cp q2.json glusterfs/heketi-storage-3-jqlwm-debug:/tmp/q2.json 
        heketi db import --dbfile heketi2.db --jsonfile /tmp/q2.json
        cp heketi2.db /var/lib/heketi/heketi.db
    * If bunch of disks is created, there are still various left-overs. First, the Gluster volumes
    have to be cleaned. The idea is to compare 'vol_' prefixed volumes in Heketi and Gluster. And
    remove ones not present in heketi. There is the script in 'ands/scripts'.
    * There is LVM volumes left from Gluster (or even allocated, but not associated with Gluster for
    various failurs. so this clean-up is worth making independently). On each node we can easily find
    volumes created today
        lvdisplay -o name,time -S 'time since "2018-03-16"'
    or again we can compare lvm volumes which are used by Gluster bricks and which are not. The later
    ones should be cleaned up. Again there is the script.
     
MySQL
=====
 - MySQL may stop replicating from the master. There is some kind of deadlock in multi-threaded SLAVE SQL.
 This can be seen by exexuting (which should show a lot of slave threads waiting on coordinator to provide
 load).
        SHOW PROCESSLIST;
 The remedy is to restart slave MySQL with 'slave_parallel_workers=0', give it a time to go, and then
 restart back in the standard multithreading mode.


     
Performance
===========
 - To find if OpenShift restricts the usage of system resources, we can 'rsh' to container and check
 cgroup limits in sysfs
    /sys/fs/cgroup/cpuset/cpuset.cpus
    /sys/fs/cgroup/memory/memory.limit_in_bytes


Various
=======
 - IPMI may cause problems as well. Particularly, the mounted CDrom may start complaining. Easiest is
 just to remove it from the running system with
     echo 1 > /sys/block/sdd/device/delete