minikube/deploy/kicbase/entrypoint

542 lines
22 KiB
Bash
Executable File

#!/bin/bash
# Copyright 2019 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
set -o errexit
set -o nounset
set -o pipefail
set -x
# If /proc/self/uid_map 4294967295 mappings, we are in the initial user namespace, i.e. the host.
# Otherwise we are in a non-initial user namespace.
# https://github.com/opencontainers/runc/blob/v1.0.0-rc92/libcontainer/system/linux.go#L109-L118
userns=""
if grep -Eqv "0[[:space:]]+0[[:space:]]+4294967295" /proc/self/uid_map; then
userns="1"
echo 'INFO: running in a user namespace (experimental)'
fi
grep_allow_nomatch() {
# grep exits 0 on match, 1 on no match, 2 on error
grep "$@" || [[ $? == 1 ]]
}
# regex_escape_ip converts IP address string $1 to a regex-escaped literal
regex_escape_ip(){
sed -e 's#\.#\\.#g' -e 's#\[#\\[#g' -e 's#\]#\\]#g' <<<"$1"
}
validate_userns() {
if [[ -z "${userns}" ]]; then
return
fi
local nofile_hard
nofile_hard="$(ulimit -Hn)"
local nofile_hard_expected="64000"
if [[ "${nofile_hard}" -lt "${nofile_hard_expected}" ]]; then
echo "WARN: UserNS: expected RLIMIT_NOFILE to be at least ${nofile_hard_expected}, got ${nofile_hard}" >&2
fi
if [[ -f "/sys/fs/cgroup/cgroup.controllers" ]]; then
for f in cpu memory pids; do
if ! grep -qw $f /sys/fs/cgroup/cgroup.controllers; then
echo "ERROR: UserNS: $f controller needs to be delegated" >&2
exit 1
fi
done
fi
}
overlayfs_preferrable() {
if [[ -z "$userns" ]]; then
# If we are outside userns, we can always assume overlayfs is preferrable
return 0
fi
# Debian 10 and 11 supports overlayfs in userns with a "permit_mount_in_userns" kernel patch,
# but known to be unstable, so we avoid using it https://github.com/moby/moby/issues/42302
if [[ -e "/sys/module/overlay/parameters/permit_mounts_in_userns" ]]; then
echo "INFO: UserNS: kernel seems supporting overlayfs with permit_mounts_in_userns, but avoiding due to instability."
return 1
fi
# Check overlayfs availability, by attempting to mount it.
#
# Overlayfs inside userns is known to be available for the following environments:
# - Kernel >= 5.11 (but 5.11 and 5.12 have issues on SELinux hosts. Fixed in 5.13.)
# - Ubuntu kernel
# - Debian kernel (but avoided due to instability, see the /sys/module/overlay/... check above)
# - Sysbox
tmp=$(mktemp -d)
mkdir -p "${tmp}/l" "${tmp}/u" "${tmp}/w" "${tmp}/m"
if ! mount -t overlay -o lowerdir="${tmp}/l,upperdir=${tmp}/u,workdir=${tmp}/w" overlay "${tmp}/m"; then
echo "INFO: UserNS: kernel does not seem to support overlayfs."
rm -rf "${tmp}"
return 1
fi
umount "${tmp}/m"
rm -rf "${tmp}"
# Detect whether SELinux is Enforcing (or Permitted) by grepping /proc/self/attr/current .
# Note that we cannot use `getenforce` command here because /sys/fs/selinux is typically not mounted for containers.
if grep -q "_t:" "/proc/self/attr/current"; then
# When the kernel is before v5.13 and SELinux is enforced, fuse-overlayfs might be safer, so we print a warning (but not an error).
# https://github.com/torvalds/linux/commit/7fa2e79a6bb924fa4b2de5766dab31f0f47b5ab6
echo "WARN: UserNS: SELinux might be Enforcing. If you see an error related to overlayfs, try setting \`KIND_EXPERIMENTAL_CONTAINERD_SNAPSHOTTER=fuse-overlayfs\` ." >&2
fi
return 0
}
configure_containerd() {
local snapshotter=${KIND_EXPERIMENTAL_CONTAINERD_SNAPSHOTTER:-}
# handle userns (rootless)
if [[ -n "$userns" ]]; then
# enable restrict_oom_score_adj
sed -i 's/restrict_oom_score_adj = false/restrict_oom_score_adj = true/' /etc/containerd/config.toml
# Use fuse-overlayfs if overlayfs is not preferrable: https://github.com/kubernetes-sigs/kind/issues/2275
if [[ -z "$snapshotter" ]] && ! overlayfs_preferrable; then
snapshotter="fuse-overlayfs"
fi
fi
# if we have not already overridden the snapshotter, attempt to auto select
if [[ -z "$snapshotter" ]]; then
# we need to switch to 'native' or 'fuse-overlayfs' on zfs
container_filesystem="$(stat -f -c %T /kind)"
if [[ "$container_filesystem" == 'zfs' ]]; then
# we do not use the ZFS snapshotter because of skew issues vs the host
snapshotter="native"
# fuse likely implies fuse-overlayfs, we should switch to fuse-overlayfs (or native)
# elif [[ "$container_filesystem" == 'fuseblk' ]]; then skipping temporarily: https://github.com/kubernetes/minikube/issues/15191
# snapshotter="fuse-overlayfs"
fi
fi
# if we've overridden or auto-selected the snapshotter vs the default, update containerd
if [[ -n "$snapshotter" ]]; then
echo "INFO: changing snapshotter from \"overlayfs\" to \"$snapshotter\""
sed -i "s/snapshotter = \"overlayfs\"/snapshotter = \"$snapshotter\"/" /etc/containerd/config.toml
if [[ "$snapshotter" = "fuse-overlayfs" ]]; then
echo 'INFO: enabling containerd-fuse-overlayfs service'
systemctl enable containerd-fuse-overlayfs
fi
fi
}
configure_proxy() {
# ensure all processes receive the proxy settings by default
# https://www.freedesktop.org/software/systemd/man/systemd-system.conf.html
mkdir -p /etc/systemd/system.conf.d/
if [[ ! -z "${NO_PROXY-}" ]]; then
NO_PROXY="${NO_PROXY},control-plane.minikube.internal"
fi
cat <<EOF >/etc/systemd/system.conf.d/proxy-default-environment.conf
[Manager]
DefaultEnvironment="HTTP_PROXY=${HTTP_PROXY:-}" "HTTPS_PROXY=${HTTPS_PROXY:-}" "NO_PROXY=${NO_PROXY:-"control-plane.minikube.internal"}"
EOF
}
update-alternatives() {
echo "retryable update-alternatives: $*"
local args=$*
for i in $(seq 0 15); do
/usr/bin/update-alternatives $args && return || echo "update-alternatives $args failed (retry $i)"
echo "update-alternatives diagnostics information below:"
mount
df -h /var
find /var/lib/dpkg
dmesg | tail
sleep 1
done
exit 30
}
fix_mount() {
echo 'INFO: ensuring we can execute mount/umount even with userns-remap'
# necessary only when userns-remap is enabled on the host, but harmless
# The binary /bin/mount should be owned by root and have the setuid bit
chown root:root "$(which mount)" "$(which umount)"
chmod -s "$(which mount)" "$(which umount)"
# This is a workaround to an AUFS bug that might cause `Text file
# busy` on `mount` command below. See more details in
# https://github.com/moby/moby/issues/9547
if [[ "$(stat -f -c %T "$(which mount)")" == 'aufs' ]]; then
echo 'INFO: detected aufs, calling sync' >&2
sync
fi
echo 'INFO: remounting /sys read-only'
# systemd-in-a-container should have read only /sys
# https://systemd.io/CONTAINER_INTERFACE/
# however, we need other things from `docker run --privileged` ...
# and this flag also happens to make /sys rw, amongst other things
#
# This step is ignored when running inside UserNS, because it fails with EACCES.
if ! mount -o remount,ro /sys; then
if [[ -n "$userns" ]]; then
echo 'INFO: UserNS: ignoring mount fail' >&2
else
exit 1
fi
fi
echo 'INFO: making mounts shared' >&2
# for mount propagation
mount --make-rshared /
}
# helper used by fix_cgroup
mount_kubelet_cgroup_root() {
local cgroup_root=$1
local subsystem=$2
if [ -z "${cgroup_root}" ]; then
return 0
fi
mkdir -p "${subsystem}/${cgroup_root}"
if [ "${subsystem}" == "/sys/fs/cgroup/cpuset" ]; then
# This is needed. Otherwise, assigning process to the cgroup
# (or any nested cgroup) would result in ENOSPC.
cat "${subsystem}/cpuset.cpus" > "${subsystem}/${cgroup_root}/cpuset.cpus"
cat "${subsystem}/cpuset.mems" > "${subsystem}/${cgroup_root}/cpuset.mems"
fi
# We need to perform a self bind mount here because otherwise,
# systemd might delete the cgroup unintentionally before the
# kubelet starts.
mount --bind "${subsystem}/${cgroup_root}" "${subsystem}/${cgroup_root}"
}
fix_cgroup() {
if [[ -f "/sys/fs/cgroup/cgroup.controllers" ]]; then
echo 'INFO: detected cgroup v2'
# Both Docker and Podman enable CgroupNS on cgroup v2 hosts by default.
#
# So mostly we do not need to mess around with the cgroup path stuff,
# however, we still need to create the "/kubelet" cgroup at least.
# (Otherwise kubelet fails with `cgroup-root ["kubelet"] doesn't exist` error, see #1969)
#
# The "/kubelet" cgroup is created in ExecStartPre of the kubeadm service.
#
# [FAQ: Why not create "/kubelet" cgroup here?]
# We can't create the cgroup with controllers here, because /sys/fs/cgroup/cgroup.subtree_control is empty.
# And yet we can't write controllers to /sys/fs/cgroup/cgroup.subtree_control by ourselves either, because
# /sys/fs/cgroup/cgroup.procs is not empty at this moment.
#
# After switching from this entrypoint script to systemd, systemd evacuates the processes in the root
# group to "/init.scope" group, so we can write the root subtree_control and create "/kubelet" cgroup.
return
fi
echo 'INFO: detected cgroup v1'
# We're looking for the cgroup-path for the cpu controller for the
# current process. this tells us what cgroup-path the container is in.
local current_cgroup
current_cgroup=$(grep -E '^[^:]*:([^:]*,)?cpu(,[^,:]*)?:.*' /proc/self/cgroup | cut -d: -f3)
if [ "$current_cgroup" = "/" ]; then
echo "INFO: cgroupns detected, no need to fix cgroups"
return
fi
# NOTE The rest of this function deals with the unfortunate situation of
# cgroup v1 with no cgroupns enabled. One fine day every user will have
# cgroupns enabled (or switch or cgroup v2 which has it enabled by default).
# Once that happens, this function can be removed completely.
echo 'WARN: cgroupns not enabled! Please use cgroup v2, or cgroup v1 with cgroupns enabled.'
# See: https://d2iq.com/blog/running-kind-inside-a-kubernetes-cluster-for-continuous-integration
# Capture initial state before modifying
#
# Then we collect the subsystems that are active on our current process.
# We assume the cpu controller is in use on all node containers,
# and other controllers use the same sub-path.
#
# See: https://man7.org/linux/man-pages/man7/cgroups.7.html
echo 'INFO: fix cgroup mounts for all subsystems'
local cgroup_subsystems
cgroup_subsystems=$(findmnt -lun -o source,target -t cgroup | grep -F "${current_cgroup}" | awk '{print $2}')
# Unmount the cgroup subsystems that are not known to runtime used to
# run the container we are in. Those subsystems are not properly scoped
# (i.e. the root cgroup is exposed, rather than something like docker/xxxx).
# In case a runtime (which is aware of more subsystems -- such as rdma,
# misc, or unified) is used inside the container, it may create cgroups for
# these subsystems, and as they are not scoped, they will leak to the host
# and thus will become non-removable.
#
# See https://github.com/kubernetes/kubernetes/issues/109182
local unsupported_cgroups
unsupported_cgroups=$(findmnt -lun -o source,target -t cgroup | grep_allow_nomatch -v -F "${current_cgroup}" | awk '{print $2}')
if [ -n "$unsupported_cgroups" ]; then
local mnt
echo "$unsupported_cgroups" |
while IFS= read -r mnt; do
echo "INFO: unmounting and removing $mnt"
umount "$mnt" || true
rmdir "$mnt" || true
done
fi
# For each cgroup subsystem, Docker does a bind mount from the current
# cgroup to the root of the cgroup subsystem. For instance:
# /sys/fs/cgroup/memory/docker/<cid> -> /sys/fs/cgroup/memory
#
# This will confuse Kubelet and cadvisor and will dump the following error
# messages in kubelet log:
# `summary_sys_containers.go:47] Failed to get system container stats for ".../kubelet.service"`
#
# This is because `/proc/<pid>/cgroup` is not affected by the bind mount.
# The following is a workaround to recreate the original cgroup
# environment by doing another bind mount for each subsystem.
local cgroup_mounts
# xref: https://github.com/kubernetes/minikube/pull/9508
# Example inputs:
#
# Docker: /docker/562a56986a84b3cd38d6a32ac43fdfcc8ad4d2473acf2839cbf549273f35c206 /sys/fs/cgroup/devices rw,nosuid,nodev,noexec,relatime shared:143 master:23 - cgroup devices rw,devices
# podman: /libpod_parent/libpod-73a4fb9769188ae5dc51cb7e24b9f2752a4af7b802a8949f06a7b2f2363ab0e9 ...
# Cloud Shell: /kubepods/besteffort/pod3d6beaa3004913efb68ce073d73494b0/accdf94879f0a494f317e9a0517f23cdd18b35ff9439efd0175f17bbc56877c4 /sys/fs/cgroup/memory rw,nosuid,nodev,noexec,relatime master:19 - cgroup cgroup rw,memory
# GitHub actions #9304: /actions_job/0924fbbcf7b18d2a00c171482b4600747afc367a9dfbeac9d6b14b35cda80399 /sys/fs/cgroup/memory rw,nosuid,nodev,noexec,relatime shared:263 master:24 - cgroup cgroup rw,memory
cgroup_mounts=$(grep -E -o '/[[:alnum:]].* /sys/fs/cgroup.*.*cgroup' /proc/self/mountinfo || true)
if [[ -n "${cgroup_mounts}" ]]; then
local mount_root
mount_root=$(head -n 1 <<<"${cgroup_mounts}" | cut -d' ' -f1)
for mount_point in $(echo "${cgroup_mounts}" | cut -d' ' -f 2); do
# bind mount each mount_point to mount_point + mount_root
# mount --bind /sys/fs/cgroup/cpu /sys/fs/cgroup/cpu/docker/fb07bb6daf7730a3cb14fc7ff3e345d1e47423756ce54409e66e01911bab2160
local target="${mount_point}${mount_root}"
if ! findmnt "${target}"; then
mkdir -p "${target}"
mount --bind "${mount_point}" "${target}"
fi
done
fi
# kubelet will try to manage cgroups / pods that are not owned by it when
# "nesting" clusters, unless we instruct it to use a different cgroup root.
# We do this, and when doing so we must fixup this alternative root
# currently this is hardcoded to be /kubelet
# under systemd cgroup driver, kubelet appends .slice
mount --make-rprivate /sys/fs/cgroup
echo "${cgroup_subsystems}" |
while IFS= read -r subsystem; do
mount_kubelet_cgroup_root /kubelet "${subsystem}"
mount_kubelet_cgroup_root /kubelet.slice "${subsystem}"
done
# workaround for hosts not running systemd
# we only do this for kubelet.slice because it's not relevant when not using
# the systemd cgroup driver
if [[ ! "${cgroup_subsystems}" = */sys/fs/cgroup/systemd* ]]; then
mount_kubelet_cgroup_root /kubelet.slice /sys/fs/cgroup/systemd
fi
}
retryable_fix_cgroup() {
for i in $(seq 0 10); do
fix_cgroup && return || echo "fix_cgroup failed with exit code $? (retry $i)"
echo "fix_cgroup diagnostics information below:"
mount
sleep 1
done
exit 31
}
fix_machine_id() {
# Deletes the machine-id embedded in the node image and generates a new one.
# This is necessary because both kubelet and other components like weave net
# use machine-id internally to distinguish nodes.
echo 'INFO: clearing and regenerating /etc/machine-id' >&2
rm -f /etc/machine-id
systemd-machine-id-setup
}
fix_product_name() {
# this is a small fix to hide the underlying hardware and fix issue #426
# https://github.com/kubernetes-sigs/kind/issues/426
if [[ -f /sys/class/dmi/id/product_name ]]; then
echo 'INFO: faking /sys/class/dmi/id/product_name to be "kind"' >&2
echo 'kind' > /kind/product_name
mount -o ro,bind /kind/product_name /sys/class/dmi/id/product_name
fi
}
fix_product_uuid() {
# The system UUID is usually read from DMI via sysfs, the problem is that
# in the kind case this means that all (container) nodes share the same
# system/product uuid, as they share the same DMI.
# Note: The UUID is read from DMI, this tool is overwriting the sysfs files
# which should fix the attached issue, but this workaround does not address
# the issue if a tool is reading directly from DMI.
# https://github.com/kubernetes-sigs/kind/issues/1027
[[ ! -f /kind/product_uuid ]] && cat /proc/sys/kernel/random/uuid > /kind/product_uuid
if [[ -f /sys/class/dmi/id/product_uuid ]]; then
echo 'INFO: faking /sys/class/dmi/id/product_uuid to be random' >&2
mount -o ro,bind /kind/product_uuid /sys/class/dmi/id/product_uuid
fi
if [[ -f /sys/devices/virtual/dmi/id/product_uuid ]]; then
echo 'INFO: faking /sys/devices/virtual/dmi/id/product_uuid as well' >&2
mount -o ro,bind /kind/product_uuid /sys/devices/virtual/dmi/id/product_uuid
fi
}
select_iptables() {
# based on: https://github.com/kubernetes-sigs/iptables-wrappers/blob/97b01f43a8e8db07840fc4b95e833a37c0d36b12/iptables-wrapper-installer.sh
local mode num_legacy_lines num_nft_lines
num_legacy_lines=$( (iptables-legacy-save || true; ip6tables-legacy-save || true) 2>/dev/null | grep -c '^-' || true)
num_nft_lines=$( (timeout 5 sh -c "iptables-nft-save; ip6tables-nft-save" || true) 2>/dev/null | grep -c '^-' || true)
if [ "${num_legacy_lines}" -ge "${num_nft_lines}" ]; then
mode=legacy
else
mode=nft
fi
echo "INFO: setting iptables to detected mode: ${mode}" >&2
update-alternatives --set iptables "/usr/sbin/iptables-${mode}" > /dev/null
update-alternatives --set ip6tables "/usr/sbin/ip6tables-${mode}" > /dev/null
}
fix_certificate() {
local apiserver_crt_file="/etc/kubernetes/pki/apiserver.crt"
local apiserver_key_file="/etc/kubernetes/pki/apiserver.key"
# Skip if this Node doesn't run kube-apiserver
if [[ ! -f ${apiserver_crt_file} ]] || [[ ! -f ${apiserver_key_file} ]]; then
return
fi
# Deletes the certificate for kube-apiserver and generates a new one.
# This is necessary because the old one doesn't match the current IP.
echo 'INFO: clearing and regenerating the certificate for serving the Kubernetes API' >&2
rm -f ${apiserver_crt_file} ${apiserver_key_file}
kubeadm init phase certs apiserver --config /kind/kubeadm.conf
}
enable_network_magic(){
# well-known docker embedded DNS is at 127.0.0.11:53
local docker_embedded_dns_ip='127.0.0.11'
# first we need to detect an IP to use for reaching the docker host
local docker_host_ip
docker_host_ip="$( (head -n1 <(timeout 5 getent ahostsv4 'host.docker.internal') | cut -d' ' -f1) || true)"
# if the ip doesn't exist or is a loopback address use the default gateway
if [[ -z "${docker_host_ip}" ]] || [[ $docker_host_ip =~ ^127\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
docker_host_ip=$(ip -4 route show default | cut -d' ' -f3)
fi
# patch docker's iptables rules to switch out the DNS IP
iptables-save \
| sed \
`# switch docker DNS DNAT rules to our chosen IP` \
-e "s/-d ${docker_embedded_dns_ip}/-d ${docker_host_ip}/g" \
`# we need to also apply these rules to non-local traffic (from pods)` \
-e 's/-A OUTPUT \(.*\) -j DOCKER_OUTPUT/\0\n-A PREROUTING \1 -j DOCKER_OUTPUT/' \
`# switch docker DNS SNAT rules rules to our chosen IP` \
-e "s/--to-source :53/--to-source ${docker_host_ip}:53/g"\
| iptables-restore
# now we can ensure that DNS is configured to use our IP
cp /etc/resolv.conf /etc/resolv.conf.original
sed -e "s/${docker_embedded_dns_ip}/${docker_host_ip}/g" /etc/resolv.conf.original >/etc/resolv.conf
local files_to_update=(
/etc/kubernetes/manifests/etcd.yaml
/etc/kubernetes/manifests/kube-apiserver.yaml
/etc/kubernetes/manifests/kube-controller-manager.yaml
/etc/kubernetes/manifests/kube-scheduler.yaml
/etc/kubernetes/controller-manager.conf
/etc/kubernetes/scheduler.conf
/kind/kubeadm.conf
/var/lib/kubelet/kubeadm-flags.env
)
local should_fix_certificate=false
# fixup IPs in manifests ...
curr_ipv4="$( (head -n1 <(timeout 5 getent ahostsv4 "$(hostname)") | cut -d' ' -f1) || true)"
echo "INFO: Detected IPv4 address: ${curr_ipv4}" >&2
if [ -f /kind/old-ipv4 ]; then
old_ipv4=$(cat /kind/old-ipv4)
echo "INFO: Detected old IPv4 address: ${old_ipv4}" >&2
# sanity check that we have a current address
if [[ -z $curr_ipv4 ]]; then
echo "ERROR: Have an old IPv4 address but no current IPv4 address (!)" >&2
exit 1
fi
if [[ "${old_ipv4}" != "${curr_ipv4}" ]]; then
should_fix_certificate=true
sed_ipv4_command="s#\b$(regex_escape_ip "${old_ipv4}")\b#${curr_ipv4}#g"
for f in "${files_to_update[@]}"; do
# kubernetes manifests are only present on control-plane nodes
if [[ -f "$f" ]]; then
sed -i "${sed_ipv4_command}" "$f"
fi
done
fi
fi
if [[ -n $curr_ipv4 ]]; then
echo -n "${curr_ipv4}" >/kind/old-ipv4
fi
# do IPv6
curr_ipv6="$( (head -n1 <(timeout 5 getent ahostsv6 "$(hostname)") | cut -d' ' -f1) || true)"
echo "INFO: Detected IPv6 address: ${curr_ipv6}" >&2
if [ -f /kind/old-ipv6 ]; then
old_ipv6=$(cat /kind/old-ipv6)
echo "INFO: Detected old IPv6 address: ${old_ipv6}" >&2
# sanity check that we have a current address
if [[ -z $curr_ipv6 ]]; then
echo "ERROR: Have an old IPv6 address but no current IPv6 address (!)" >&2
fi
if [[ "${old_ipv6}" != "${curr_ipv6}" ]]; then
should_fix_certificate=true
sed_ipv6_command="s#\b$(regex_escape_ip "${old_ipv6}")\b#${curr_ipv6}#g"
for f in "${files_to_update[@]}"; do
# kubernetes manifests are only present on control-plane nodes
if [[ -f "$f" ]]; then
sed -i "${sed_ipv6_command}" "$f"
fi
done
fi
fi
if [[ -n $curr_ipv6 ]]; then
echo -n "${curr_ipv6}" >/kind/old-ipv6
fi
if $should_fix_certificate; then
fix_certificate
fi
}
# validate state
validate_userns
# run pre-init fixups
# NOTE: it's important that we do configure* first in this order to avoid races
configure_containerd
configure_proxy
fix_mount
retryable_fix_cgroup
fix_machine_id
fix_product_name
fix_product_uuid
select_iptables
enable_network_magic
echo "entrypoint completed: $(uname -a)"
# we want the command (expected to be systemd) to be PID1, so exec to it
exec "$@"